Calculus Examples

Find the Local Maxima and Minima f(x) = square root of x^3+3x^2
Step 1
Find the first derivative of the function.
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Step 1.1
Rewrite as .
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Step 1.1.1
Rewrite as .
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Step 1.1.1.1
Factor out of .
Step 1.1.1.2
Factor out of .
Step 1.1.1.3
Factor out of .
Step 1.1.2
Pull terms out from under the radical.
Step 1.2
Use to rewrite as .
Step 1.3
Differentiate using the Product Rule which states that is where and .
Step 1.4
Differentiate using the chain rule, which states that is where and .
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Step 1.4.1
To apply the Chain Rule, set as .
Step 1.4.2
Differentiate using the Power Rule which states that is where .
Step 1.4.3
Replace all occurrences of with .
Step 1.5
To write as a fraction with a common denominator, multiply by .
Step 1.6
Combine and .
Step 1.7
Combine the numerators over the common denominator.
Step 1.8
Simplify the numerator.
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Step 1.8.1
Multiply by .
Step 1.8.2
Subtract from .
Step 1.9
Combine fractions.
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Step 1.9.1
Move the negative in front of the fraction.
Step 1.9.2
Combine and .
Step 1.9.3
Move to the denominator using the negative exponent rule .
Step 1.9.4
Combine and .
Step 1.10
By the Sum Rule, the derivative of with respect to is .
Step 1.11
Differentiate using the Power Rule which states that is where .
Step 1.12
Since is constant with respect to , the derivative of with respect to is .
Step 1.13
Simplify the expression.
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Step 1.13.1
Add and .
Step 1.13.2
Multiply by .
Step 1.14
Differentiate using the Power Rule which states that is where .
Step 1.15
Multiply by .
Step 1.16
To write as a fraction with a common denominator, multiply by .
Step 1.17
Combine and .
Step 1.18
Combine the numerators over the common denominator.
Step 1.19
Multiply by by adding the exponents.
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Step 1.19.1
Move .
Step 1.19.2
Use the power rule to combine exponents.
Step 1.19.3
Combine the numerators over the common denominator.
Step 1.19.4
Add and .
Step 1.19.5
Divide by .
Step 1.20
Simplify .
Step 1.21
Move to the left of .
Step 1.22
Simplify.
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Step 1.22.1
Apply the distributive property.
Step 1.22.2
Simplify the numerator.
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Step 1.22.2.1
Multiply by .
Step 1.22.2.2
Add and .
Step 1.22.3
Factor out of .
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Step 1.22.3.1
Factor out of .
Step 1.22.3.2
Factor out of .
Step 1.22.3.3
Factor out of .
Step 2
Find the second derivative of the function.
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Step 2.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.2
Differentiate using the Quotient Rule which states that is where and .
Step 2.3
Multiply the exponents in .
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Step 2.3.1
Apply the power rule and multiply exponents, .
Step 2.3.2
Cancel the common factor of .
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Step 2.3.2.1
Cancel the common factor.
Step 2.3.2.2
Rewrite the expression.
Step 2.4
Simplify.
Step 2.5
Differentiate.
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Step 2.5.1
By the Sum Rule, the derivative of with respect to is .
Step 2.5.2
Differentiate using the Power Rule which states that is where .
Step 2.5.3
Since is constant with respect to , the derivative of with respect to is .
Step 2.5.4
Simplify the expression.
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Step 2.5.4.1
Add and .
Step 2.5.4.2
Multiply by .
Step 2.6
Differentiate using the chain rule, which states that is where and .
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Step 2.6.1
To apply the Chain Rule, set as .
Step 2.6.2
Differentiate using the Power Rule which states that is where .
Step 2.6.3
Replace all occurrences of with .
Step 2.7
To write as a fraction with a common denominator, multiply by .
Step 2.8
Combine and .
Step 2.9
Combine the numerators over the common denominator.
Step 2.10
Simplify the numerator.
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Step 2.10.1
Multiply by .
Step 2.10.2
Subtract from .
Step 2.11
Combine fractions.
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Step 2.11.1
Move the negative in front of the fraction.
Step 2.11.2
Combine and .
Step 2.11.3
Move to the denominator using the negative exponent rule .
Step 2.12
By the Sum Rule, the derivative of with respect to is .
Step 2.13
Differentiate using the Power Rule which states that is where .
Step 2.14
Since is constant with respect to , the derivative of with respect to is .
Step 2.15
Combine fractions.
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Step 2.15.1
Add and .
Step 2.15.2
Multiply by .
Step 2.15.3
Multiply by .
Step 2.16
Simplify.
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Step 2.16.1
Apply the distributive property.
Step 2.16.2
Apply the distributive property.
Step 2.16.3
Apply the distributive property.
Step 2.16.4
Simplify the numerator.
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Step 2.16.4.1
Factor out of .
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Step 2.16.4.1.1
Factor out of .
Step 2.16.4.1.2
Factor out of .
Step 2.16.4.1.3
Factor out of .
Step 2.16.4.2
Let . Substitute for all occurrences of .
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Step 2.16.4.2.1
Rewrite using the commutative property of multiplication.
Step 2.16.4.2.2
Multiply by by adding the exponents.
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Step 2.16.4.2.2.1
Move .
Step 2.16.4.2.2.2
Multiply by .
Step 2.16.4.3
Replace all occurrences of with .
Step 2.16.4.4
Simplify.
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Step 2.16.4.4.1
Simplify each term.
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Step 2.16.4.4.1.1
Multiply the exponents in .
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Step 2.16.4.4.1.1.1
Apply the power rule and multiply exponents, .
Step 2.16.4.4.1.1.2
Cancel the common factor of .
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Step 2.16.4.4.1.1.2.1
Cancel the common factor.
Step 2.16.4.4.1.1.2.2
Rewrite the expression.
Step 2.16.4.4.1.2
Simplify.
Step 2.16.4.4.1.3
Apply the distributive property.
Step 2.16.4.4.1.4
Multiply by .
Step 2.16.4.4.2
Subtract from .
Step 2.16.4.4.3
Subtract from .
Step 2.16.5
Combine terms.
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Step 2.16.5.1
Combine and .
Step 2.16.5.2
Multiply by .
Step 2.16.5.3
Rewrite as a product.
Step 2.16.5.4
Multiply by .
Step 2.16.6
Simplify the denominator.
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Step 2.16.6.1
Factor out of .
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Step 2.16.6.1.1
Factor out of .
Step 2.16.6.1.2
Factor out of .
Step 2.16.6.1.3
Factor out of .
Step 2.16.6.2
Combine exponents.
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Step 2.16.6.2.1
Multiply by .
Step 2.16.6.2.2
Raise to the power of .
Step 2.16.6.2.3
Use the power rule to combine exponents.
Step 2.16.6.2.4
Write as a fraction with a common denominator.
Step 2.16.6.2.5
Combine the numerators over the common denominator.
Step 2.16.6.2.6
Add and .
Step 3
To find the local maximum and minimum values of the function, set the derivative equal to and solve.
Step 4
Find the first derivative.
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Step 4.1
Find the first derivative.
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Step 4.1.1
Rewrite as .
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Step 4.1.1.1
Rewrite as .
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Step 4.1.1.1.1
Factor out of .
Step 4.1.1.1.2
Factor out of .
Step 4.1.1.1.3
Factor out of .
Step 4.1.1.2
Pull terms out from under the radical.
Step 4.1.2
Use to rewrite as .
Step 4.1.3
Differentiate using the Product Rule which states that is where and .
Step 4.1.4
Differentiate using the chain rule, which states that is where and .
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Step 4.1.4.1
To apply the Chain Rule, set as .
Step 4.1.4.2
Differentiate using the Power Rule which states that is where .
Step 4.1.4.3
Replace all occurrences of with .
Step 4.1.5
To write as a fraction with a common denominator, multiply by .
Step 4.1.6
Combine and .
Step 4.1.7
Combine the numerators over the common denominator.
Step 4.1.8
Simplify the numerator.
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Step 4.1.8.1
Multiply by .
Step 4.1.8.2
Subtract from .
Step 4.1.9
Combine fractions.
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Step 4.1.9.1
Move the negative in front of the fraction.
Step 4.1.9.2
Combine and .
Step 4.1.9.3
Move to the denominator using the negative exponent rule .
Step 4.1.9.4
Combine and .
Step 4.1.10
By the Sum Rule, the derivative of with respect to is .
Step 4.1.11
Differentiate using the Power Rule which states that is where .
Step 4.1.12
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.13
Simplify the expression.
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Step 4.1.13.1
Add and .
Step 4.1.13.2
Multiply by .
Step 4.1.14
Differentiate using the Power Rule which states that is where .
Step 4.1.15
Multiply by .
Step 4.1.16
To write as a fraction with a common denominator, multiply by .
Step 4.1.17
Combine and .
Step 4.1.18
Combine the numerators over the common denominator.
Step 4.1.19
Multiply by by adding the exponents.
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Step 4.1.19.1
Move .
Step 4.1.19.2
Use the power rule to combine exponents.
Step 4.1.19.3
Combine the numerators over the common denominator.
Step 4.1.19.4
Add and .
Step 4.1.19.5
Divide by .
Step 4.1.20
Simplify .
Step 4.1.21
Move to the left of .
Step 4.1.22
Simplify.
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Step 4.1.22.1
Apply the distributive property.
Step 4.1.22.2
Simplify the numerator.
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Step 4.1.22.2.1
Multiply by .
Step 4.1.22.2.2
Add and .
Step 4.1.22.3
Factor out of .
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Step 4.1.22.3.1
Factor out of .
Step 4.1.22.3.2
Factor out of .
Step 4.1.22.3.3
Factor out of .
Step 4.2
The first derivative of with respect to is .
Step 5
Set the first derivative equal to then solve the equation .
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Step 5.1
Set the first derivative equal to .
Step 5.2
Set the numerator equal to zero.
Step 5.3
Solve the equation for .
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Step 5.3.1
Divide each term in by and simplify.
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Step 5.3.1.1
Divide each term in by .
Step 5.3.1.2
Simplify the left side.
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Step 5.3.1.2.1
Cancel the common factor of .
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Step 5.3.1.2.1.1
Cancel the common factor.
Step 5.3.1.2.1.2
Divide by .
Step 5.3.1.3
Simplify the right side.
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Step 5.3.1.3.1
Divide by .
Step 5.3.2
Subtract from both sides of the equation.
Step 6
Find the values where the derivative is undefined.
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Step 6.1
Convert expressions with fractional exponents to radicals.
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Step 6.1.1
Apply the rule to rewrite the exponentiation as a radical.
Step 6.1.2
Anything raised to is the base itself.
Step 6.2
Set the denominator in equal to to find where the expression is undefined.
Step 6.3
Solve for .
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Step 6.3.1
To remove the radical on the left side of the equation, square both sides of the equation.
Step 6.3.2
Simplify each side of the equation.
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Step 6.3.2.1
Use to rewrite as .
Step 6.3.2.2
Simplify the left side.
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Step 6.3.2.2.1
Simplify .
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Step 6.3.2.2.1.1
Apply the product rule to .
Step 6.3.2.2.1.2
Raise to the power of .
Step 6.3.2.2.1.3
Multiply the exponents in .
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Step 6.3.2.2.1.3.1
Apply the power rule and multiply exponents, .
Step 6.3.2.2.1.3.2
Cancel the common factor of .
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Step 6.3.2.2.1.3.2.1
Cancel the common factor.
Step 6.3.2.2.1.3.2.2
Rewrite the expression.
Step 6.3.2.2.1.4
Simplify.
Step 6.3.2.2.1.5
Apply the distributive property.
Step 6.3.2.2.1.6
Multiply by .
Step 6.3.2.3
Simplify the right side.
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Step 6.3.2.3.1
Raising to any positive power yields .
Step 6.3.3
Solve for .
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Step 6.3.3.1
Subtract from both sides of the equation.
Step 6.3.3.2
Divide each term in by and simplify.
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Step 6.3.3.2.1
Divide each term in by .
Step 6.3.3.2.2
Simplify the left side.
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Step 6.3.3.2.2.1
Cancel the common factor of .
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Step 6.3.3.2.2.1.1
Cancel the common factor.
Step 6.3.3.2.2.1.2
Divide by .
Step 6.3.3.2.3
Simplify the right side.
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Step 6.3.3.2.3.1
Divide by .
Step 6.4
Set the radicand in less than to find where the expression is undefined.
Step 6.5
Subtract from both sides of the inequality.
Step 6.6
The equation is undefined where the denominator equals , the argument of a square root is less than , or the argument of a logarithm is less than or equal to .
Step 7
Critical points to evaluate.
Step 8
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 9
Evaluate the second derivative.
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Step 9.1
Factor out of .
Step 9.2
Cancel the common factors.
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Step 9.2.1
Factor out of .
Step 9.2.2
Cancel the common factor.
Step 9.2.3
Rewrite the expression.
Step 9.3
Add and .
Step 9.4
Simplify the denominator.
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Step 9.4.1
Add and .
Step 9.4.2
One to any power is one.
Step 9.5
Simplify.
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Step 9.5.1
Multiply by .
Step 9.5.2
Multiply by .
Step 10
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 11
Find the y-value when .
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Step 11.1
Replace the variable with in the expression.
Step 11.2
Simplify the result.
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Step 11.2.1
Raise to the power of .
Step 11.2.2
Raise to the power of .
Step 11.2.3
Multiply by .
Step 11.2.4
Add and .
Step 11.2.5
Rewrite as .
Step 11.2.6
Pull terms out from under the radical, assuming positive real numbers.
Step 11.2.7
The final answer is .
Step 12
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 13
Evaluate the second derivative.
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Step 13.1
Simplify the expression.
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Step 13.1.1
Add and .
Step 13.1.2
Rewrite as .
Step 13.1.3
Apply the power rule and multiply exponents, .
Step 13.2
Cancel the common factor of .
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Step 13.2.1
Cancel the common factor.
Step 13.2.2
Rewrite the expression.
Step 13.3
Simplify the expression.
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Step 13.3.1
Raising to any positive power yields .
Step 13.3.2
Multiply by .
Step 13.3.3
The expression contains a division by . The expression is undefined.
Undefined
Step 13.4
The expression contains a division by . The expression is undefined.
Undefined
Undefined
Step 14
Since the first derivative test failed, there are no local extrema.
No Local Extrema
Step 15