Calculus Examples

Find the Local Maxima and Minima 4x^3-27/2x^2+8x
Step 1
Write as a function.
Step 2
Find the first derivative of the function.
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Step 2.1
By the Sum Rule, the derivative of with respect to is .
Step 2.2
Evaluate .
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Step 2.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.2.2
Differentiate using the Power Rule which states that is where .
Step 2.2.3
Multiply by .
Step 2.3
Evaluate .
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Step 2.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.3.2
Differentiate using the Power Rule which states that is where .
Step 2.3.3
Multiply by .
Step 2.3.4
Combine and .
Step 2.3.5
Multiply by .
Step 2.3.6
Combine and .
Step 2.3.7
Cancel the common factor of and .
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Step 2.3.7.1
Factor out of .
Step 2.3.7.2
Cancel the common factors.
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Step 2.3.7.2.1
Factor out of .
Step 2.3.7.2.2
Cancel the common factor.
Step 2.3.7.2.3
Rewrite the expression.
Step 2.3.7.2.4
Divide by .
Step 2.4
Evaluate .
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Step 2.4.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.4.2
Differentiate using the Power Rule which states that is where .
Step 2.4.3
Multiply by .
Step 3
Find the second derivative of the function.
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Step 3.1
By the Sum Rule, the derivative of with respect to is .
Step 3.2
Evaluate .
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Step 3.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 3.2.2
Differentiate using the Power Rule which states that is where .
Step 3.2.3
Multiply by .
Step 3.3
Evaluate .
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Step 3.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 3.3.2
Differentiate using the Power Rule which states that is where .
Step 3.3.3
Multiply by .
Step 3.4
Differentiate using the Constant Rule.
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Step 3.4.1
Since is constant with respect to , the derivative of with respect to is .
Step 3.4.2
Add and .
Step 4
To find the local maximum and minimum values of the function, set the derivative equal to and solve.
Step 5
Find the first derivative.
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Step 5.1
Find the first derivative.
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Step 5.1.1
By the Sum Rule, the derivative of with respect to is .
Step 5.1.2
Evaluate .
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Step 5.1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 5.1.2.2
Differentiate using the Power Rule which states that is where .
Step 5.1.2.3
Multiply by .
Step 5.1.3
Evaluate .
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Step 5.1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 5.1.3.2
Differentiate using the Power Rule which states that is where .
Step 5.1.3.3
Multiply by .
Step 5.1.3.4
Combine and .
Step 5.1.3.5
Multiply by .
Step 5.1.3.6
Combine and .
Step 5.1.3.7
Cancel the common factor of and .
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Step 5.1.3.7.1
Factor out of .
Step 5.1.3.7.2
Cancel the common factors.
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Step 5.1.3.7.2.1
Factor out of .
Step 5.1.3.7.2.2
Cancel the common factor.
Step 5.1.3.7.2.3
Rewrite the expression.
Step 5.1.3.7.2.4
Divide by .
Step 5.1.4
Evaluate .
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Step 5.1.4.1
Since is constant with respect to , the derivative of with respect to is .
Step 5.1.4.2
Differentiate using the Power Rule which states that is where .
Step 5.1.4.3
Multiply by .
Step 5.2
The first derivative of with respect to is .
Step 6
Set the first derivative equal to then solve the equation .
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Step 6.1
Set the first derivative equal to .
Step 6.2
Use the quadratic formula to find the solutions.
Step 6.3
Substitute the values , , and into the quadratic formula and solve for .
Step 6.4
Simplify.
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Step 6.4.1
Simplify the numerator.
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Step 6.4.1.1
Raise to the power of .
Step 6.4.1.2
Multiply .
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Step 6.4.1.2.1
Multiply by .
Step 6.4.1.2.2
Multiply by .
Step 6.4.1.3
Subtract from .
Step 6.4.2
Multiply by .
Step 6.5
Simplify the expression to solve for the portion of the .
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Step 6.5.1
Simplify the numerator.
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Step 6.5.1.1
Raise to the power of .
Step 6.5.1.2
Multiply .
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Step 6.5.1.2.1
Multiply by .
Step 6.5.1.2.2
Multiply by .
Step 6.5.1.3
Subtract from .
Step 6.5.2
Multiply by .
Step 6.5.3
Change the to .
Step 6.6
Simplify the expression to solve for the portion of the .
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Step 6.6.1
Simplify the numerator.
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Step 6.6.1.1
Raise to the power of .
Step 6.6.1.2
Multiply .
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Step 6.6.1.2.1
Multiply by .
Step 6.6.1.2.2
Multiply by .
Step 6.6.1.3
Subtract from .
Step 6.6.2
Multiply by .
Step 6.6.3
Change the to .
Step 6.7
The final answer is the combination of both solutions.
Step 7
Find the values where the derivative is undefined.
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Step 7.1
The domain of the expression is all real numbers except where the expression is undefined. In this case, there is no real number that makes the expression undefined.
Step 8
Critical points to evaluate.
Step 9
Evaluate the second derivative at . If the second derivative is positive, then this is a local minimum. If it is negative, then this is a local maximum.
Step 10
Evaluate the second derivative.
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Step 10.1
Cancel the common factor of .
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Step 10.1.1
Cancel the common factor.
Step 10.1.2
Rewrite the expression.
Step 10.2
Simplify by subtracting numbers.
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Step 10.2.1
Subtract from .
Step 10.2.2
Add and .
Step 11
is a local minimum because the value of the second derivative is positive. This is referred to as the second derivative test.
is a local minimum
Step 12
Find the y-value when .
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Step 12.1
Replace the variable with in the expression.
Step 12.2
Simplify the result.
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Step 12.2.1
Simplify each term.
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Step 12.2.1.1
Apply the product rule to .
Step 12.2.1.2
Raise to the power of .
Step 12.2.1.3
Cancel the common factor of .
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Step 12.2.1.3.1
Factor out of .
Step 12.2.1.3.2
Cancel the common factor.
Step 12.2.1.3.3
Rewrite the expression.
Step 12.2.1.4
Use the Binomial Theorem.
Step 12.2.1.5
Simplify each term.
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Step 12.2.1.5.1
Raise to the power of .
Step 12.2.1.5.2
Raise to the power of .
Step 12.2.1.5.3
Multiply by .
Step 12.2.1.5.4
Multiply by .
Step 12.2.1.5.5
Rewrite as .
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Step 12.2.1.5.5.1
Use to rewrite as .
Step 12.2.1.5.5.2
Apply the power rule and multiply exponents, .
Step 12.2.1.5.5.3
Combine and .
Step 12.2.1.5.5.4
Cancel the common factor of .
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Step 12.2.1.5.5.4.1
Cancel the common factor.
Step 12.2.1.5.5.4.2
Rewrite the expression.
Step 12.2.1.5.5.5
Evaluate the exponent.
Step 12.2.1.5.6
Multiply by .
Step 12.2.1.5.7
Rewrite as .
Step 12.2.1.5.8
Raise to the power of .
Step 12.2.1.5.9
Rewrite as .
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Step 12.2.1.5.9.1
Factor out of .
Step 12.2.1.5.9.2
Rewrite as .
Step 12.2.1.5.10
Pull terms out from under the radical.
Step 12.2.1.6
Add and .
Step 12.2.1.7
Add and .
Step 12.2.1.8
Cancel the common factor of and .
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Step 12.2.1.8.1
Factor out of .
Step 12.2.1.8.2
Factor out of .
Step 12.2.1.8.3
Factor out of .
Step 12.2.1.8.4
Cancel the common factors.
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Step 12.2.1.8.4.1
Factor out of .
Step 12.2.1.8.4.2
Cancel the common factor.
Step 12.2.1.8.4.3
Rewrite the expression.
Step 12.2.1.9
Apply the product rule to .
Step 12.2.1.10
Raise to the power of .
Step 12.2.1.11
Cancel the common factor of .
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Step 12.2.1.11.1
Move the leading negative in into the numerator.
Step 12.2.1.11.2
Factor out of .
Step 12.2.1.11.3
Factor out of .
Step 12.2.1.11.4
Cancel the common factor.
Step 12.2.1.11.5
Rewrite the expression.
Step 12.2.1.12
Multiply by .
Step 12.2.1.13
Multiply by .
Step 12.2.1.14
Rewrite as .
Step 12.2.1.15
Expand using the FOIL Method.
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Step 12.2.1.15.1
Apply the distributive property.
Step 12.2.1.15.2
Apply the distributive property.
Step 12.2.1.15.3
Apply the distributive property.
Step 12.2.1.16
Simplify and combine like terms.
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Step 12.2.1.16.1
Simplify each term.
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Step 12.2.1.16.1.1
Multiply by .
Step 12.2.1.16.1.2
Move to the left of .
Step 12.2.1.16.1.3
Combine using the product rule for radicals.
Step 12.2.1.16.1.4
Multiply by .
Step 12.2.1.16.1.5
Rewrite as .
Step 12.2.1.16.1.6
Pull terms out from under the radical, assuming positive real numbers.
Step 12.2.1.16.2
Add and .
Step 12.2.1.16.3
Add and .
Step 12.2.1.17
Cancel the common factor of and .
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Step 12.2.1.17.1
Factor out of .
Step 12.2.1.17.2
Cancel the common factors.
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Step 12.2.1.17.2.1
Factor out of .
Step 12.2.1.17.2.2
Cancel the common factor.
Step 12.2.1.17.2.3
Rewrite the expression.
Step 12.2.1.18
Move the negative in front of the fraction.
Step 12.2.1.19
Cancel the common factor of .
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Step 12.2.1.19.1
Factor out of .
Step 12.2.1.19.2
Cancel the common factor.
Step 12.2.1.19.3
Rewrite the expression.
Step 12.2.2
Find the common denominator.
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Step 12.2.2.1
Multiply by .
Step 12.2.2.2
Multiply by .
Step 12.2.2.3
Multiply by .
Step 12.2.2.4
Multiply by .
Step 12.2.2.5
Multiply by .
Step 12.2.2.6
Multiply by .
Step 12.2.2.7
Reorder the factors of .
Step 12.2.2.8
Multiply by .
Step 12.2.2.9
Reorder the factors of .
Step 12.2.2.10
Multiply by .
Step 12.2.2.11
Multiply by .
Step 12.2.3
Combine the numerators over the common denominator.
Step 12.2.4
Simplify each term.
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Step 12.2.4.1
Apply the distributive property.
Step 12.2.4.2
Multiply by .
Step 12.2.4.3
Multiply by .
Step 12.2.4.4
Apply the distributive property.
Step 12.2.4.5
Multiply by .
Step 12.2.4.6
Multiply by .
Step 12.2.4.7
Apply the distributive property.
Step 12.2.4.8
Multiply by .
Step 12.2.4.9
Multiply by .
Step 12.2.4.10
Apply the distributive property.
Step 12.2.4.11
Multiply by .
Step 12.2.4.12
Move to the left of .
Step 12.2.5
Simplify terms.
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Step 12.2.5.1
Subtract from .
Step 12.2.5.2
Add and .
Step 12.2.5.3
Subtract from .
Step 12.2.5.4
Add and .
Step 12.2.5.5
Rewrite as .
Step 12.2.5.6
Factor out of .
Step 12.2.5.7
Factor out of .
Step 12.2.5.8
Move the negative in front of the fraction.
Step 12.2.6
The final answer is .
Step 13
Evaluate the second derivative at . If the second derivative is positive, then this is a local minimum. If it is negative, then this is a local maximum.
Step 14
Evaluate the second derivative.
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Step 14.1
Cancel the common factor of .
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Step 14.1.1
Cancel the common factor.
Step 14.1.2
Rewrite the expression.
Step 14.2
Simplify by subtracting numbers.
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Step 14.2.1
Subtract from .
Step 14.2.2
Subtract from .
Step 15
is a local maximum because the value of the second derivative is negative. This is referred to as the second derivative test.
is a local maximum
Step 16
Find the y-value when .
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Step 16.1
Replace the variable with in the expression.
Step 16.2
Simplify the result.
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Step 16.2.1
Simplify each term.
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Step 16.2.1.1
Apply the product rule to .
Step 16.2.1.2
Raise to the power of .
Step 16.2.1.3
Cancel the common factor of .
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Step 16.2.1.3.1
Factor out of .
Step 16.2.1.3.2
Cancel the common factor.
Step 16.2.1.3.3
Rewrite the expression.
Step 16.2.1.4
Use the Binomial Theorem.
Step 16.2.1.5
Simplify each term.
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Step 16.2.1.5.1
Raise to the power of .
Step 16.2.1.5.2
Raise to the power of .
Step 16.2.1.5.3
Multiply by .
Step 16.2.1.5.4
Multiply by .
Step 16.2.1.5.5
Multiply by .
Step 16.2.1.5.6
Apply the product rule to .
Step 16.2.1.5.7
Raise to the power of .
Step 16.2.1.5.8
Multiply by .
Step 16.2.1.5.9
Rewrite as .
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Step 16.2.1.5.9.1
Use to rewrite as .
Step 16.2.1.5.9.2
Apply the power rule and multiply exponents, .
Step 16.2.1.5.9.3
Combine and .
Step 16.2.1.5.9.4
Cancel the common factor of .
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Step 16.2.1.5.9.4.1
Cancel the common factor.
Step 16.2.1.5.9.4.2
Rewrite the expression.
Step 16.2.1.5.9.5
Evaluate the exponent.
Step 16.2.1.5.10
Multiply by .
Step 16.2.1.5.11
Apply the product rule to .
Step 16.2.1.5.12
Raise to the power of .
Step 16.2.1.5.13
Rewrite as .
Step 16.2.1.5.14
Raise to the power of .
Step 16.2.1.5.15
Rewrite as .
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Step 16.2.1.5.15.1
Factor out of .
Step 16.2.1.5.15.2
Rewrite as .
Step 16.2.1.5.16
Pull terms out from under the radical.
Step 16.2.1.5.17
Multiply by .
Step 16.2.1.6
Add and .
Step 16.2.1.7
Subtract from .
Step 16.2.1.8
Cancel the common factor of and .
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Step 16.2.1.8.1
Factor out of .
Step 16.2.1.8.2
Factor out of .
Step 16.2.1.8.3
Factor out of .
Step 16.2.1.8.4
Cancel the common factors.
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Step 16.2.1.8.4.1
Factor out of .
Step 16.2.1.8.4.2
Cancel the common factor.
Step 16.2.1.8.4.3
Rewrite the expression.
Step 16.2.1.9
Apply the product rule to .
Step 16.2.1.10
Raise to the power of .
Step 16.2.1.11
Cancel the common factor of .
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Step 16.2.1.11.1
Move the leading negative in into the numerator.
Step 16.2.1.11.2
Factor out of .
Step 16.2.1.11.3
Factor out of .
Step 16.2.1.11.4
Cancel the common factor.
Step 16.2.1.11.5
Rewrite the expression.
Step 16.2.1.12
Multiply by .
Step 16.2.1.13
Multiply by .
Step 16.2.1.14
Rewrite as .
Step 16.2.1.15
Expand using the FOIL Method.
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Step 16.2.1.15.1
Apply the distributive property.
Step 16.2.1.15.2
Apply the distributive property.
Step 16.2.1.15.3
Apply the distributive property.
Step 16.2.1.16
Simplify and combine like terms.
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Step 16.2.1.16.1
Simplify each term.
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Step 16.2.1.16.1.1
Multiply by .
Step 16.2.1.16.1.2
Multiply by .
Step 16.2.1.16.1.3
Multiply by .
Step 16.2.1.16.1.4
Multiply .
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Step 16.2.1.16.1.4.1
Multiply by .
Step 16.2.1.16.1.4.2
Multiply by .
Step 16.2.1.16.1.4.3
Raise to the power of .
Step 16.2.1.16.1.4.4
Raise to the power of .
Step 16.2.1.16.1.4.5
Use the power rule to combine exponents.
Step 16.2.1.16.1.4.6
Add and .
Step 16.2.1.16.1.5
Rewrite as .
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Step 16.2.1.16.1.5.1
Use to rewrite as .
Step 16.2.1.16.1.5.2
Apply the power rule and multiply exponents, .
Step 16.2.1.16.1.5.3
Combine and .
Step 16.2.1.16.1.5.4
Cancel the common factor of .
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Step 16.2.1.16.1.5.4.1
Cancel the common factor.
Step 16.2.1.16.1.5.4.2
Rewrite the expression.
Step 16.2.1.16.1.5.5
Evaluate the exponent.
Step 16.2.1.16.2
Add and .
Step 16.2.1.16.3
Subtract from .
Step 16.2.1.17
Cancel the common factor of and .
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Step 16.2.1.17.1
Factor out of .
Step 16.2.1.17.2
Cancel the common factors.
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Step 16.2.1.17.2.1
Factor out of .
Step 16.2.1.17.2.2
Cancel the common factor.
Step 16.2.1.17.2.3
Rewrite the expression.
Step 16.2.1.18
Move the negative in front of the fraction.
Step 16.2.1.19
Cancel the common factor of .
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Step 16.2.1.19.1
Factor out of .
Step 16.2.1.19.2
Cancel the common factor.
Step 16.2.1.19.3
Rewrite the expression.
Step 16.2.2
Find the common denominator.
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Step 16.2.2.1
Multiply by .
Step 16.2.2.2
Multiply by .
Step 16.2.2.3
Multiply by .
Step 16.2.2.4
Multiply by .
Step 16.2.2.5
Multiply by .
Step 16.2.2.6
Multiply by .
Step 16.2.2.7
Reorder the factors of .
Step 16.2.2.8
Multiply by .
Step 16.2.2.9
Reorder the factors of .
Step 16.2.2.10
Multiply by .
Step 16.2.2.11
Multiply by .
Step 16.2.3
Combine the numerators over the common denominator.
Step 16.2.4
Simplify each term.
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Step 16.2.4.1
Apply the distributive property.
Step 16.2.4.2
Multiply by .
Step 16.2.4.3
Multiply by .
Step 16.2.4.4
Apply the distributive property.
Step 16.2.4.5
Multiply by .
Step 16.2.4.6
Multiply by .
Step 16.2.4.7
Apply the distributive property.
Step 16.2.4.8
Multiply by .
Step 16.2.4.9
Multiply by .
Step 16.2.4.10
Apply the distributive property.
Step 16.2.4.11
Multiply by .
Step 16.2.4.12
Multiply by .
Step 16.2.5
Simplify terms.
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Step 16.2.5.1
Subtract from .
Step 16.2.5.2
Add and .
Step 16.2.5.3
Add and .
Step 16.2.5.4
Subtract from .
Step 16.2.5.5
Rewrite as .
Step 16.2.5.6
Factor out of .
Step 16.2.5.7
Factor out of .
Step 16.2.5.8
Move the negative in front of the fraction.
Step 16.2.6
The final answer is .
Step 17
These are the local extrema for .
is a local minima
is a local maxima
Step 18