Calculus Examples

Find the Local Maxima and Minima (x^2-2x)e^x
Step 1
Write as a function.
Step 2
Find the first derivative of the function.
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Step 2.1
Differentiate using the Product Rule which states that is where and .
Step 2.2
Differentiate using the Exponential Rule which states that is where =.
Step 2.3
Differentiate.
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Step 2.3.1
By the Sum Rule, 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
Since is constant with respect to , the derivative of with respect to is .
Step 2.3.4
Differentiate using the Power Rule which states that is where .
Step 2.3.5
Multiply by .
Step 2.4
Simplify.
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Step 2.4.1
Apply the distributive property.
Step 2.4.2
Apply the distributive property.
Step 2.4.3
Combine terms.
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Step 2.4.3.1
Move to the left of .
Step 2.4.3.2
Add and .
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Step 2.4.3.2.1
Move .
Step 2.4.3.2.2
Add and .
Step 2.4.3.3
Add and .
Step 2.4.4
Reorder terms.
Step 2.4.5
Reorder factors in .
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
Differentiate using the Product Rule which states that is where and .
Step 3.2.2
Differentiate using the Exponential Rule which states that is where =.
Step 3.2.3
Differentiate using the Power Rule which states that is where .
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 Exponential Rule which states that is where =.
Step 3.4
Simplify.
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Step 3.4.1
Reorder terms.
Step 3.4.2
Reorder factors in .
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
Differentiate using the Product Rule which states that is where and .
Step 5.1.2
Differentiate using the Exponential Rule which states that is where =.
Step 5.1.3
Differentiate.
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Step 5.1.3.1
By the Sum Rule, 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
Since is constant with respect to , the derivative of with respect to is .
Step 5.1.3.4
Differentiate using the Power Rule which states that is where .
Step 5.1.3.5
Multiply by .
Step 5.1.4
Simplify.
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Step 5.1.4.1
Apply the distributive property.
Step 5.1.4.2
Apply the distributive property.
Step 5.1.4.3
Combine terms.
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Step 5.1.4.3.1
Move to the left of .
Step 5.1.4.3.2
Add and .
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Step 5.1.4.3.2.1
Move .
Step 5.1.4.3.2.2
Add and .
Step 5.1.4.3.3
Add and .
Step 5.1.4.4
Reorder terms.
Step 5.1.4.5
Reorder factors in .
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
Factor out of .
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Step 6.2.1
Factor out of .
Step 6.2.2
Factor out of .
Step 6.2.3
Factor out of .
Step 6.3
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 6.4
Set equal to and solve for .
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Step 6.4.1
Set equal to .
Step 6.4.2
Solve for .
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Step 6.4.2.1
Take the natural logarithm of both sides of the equation to remove the variable from the exponent.
Step 6.4.2.2
The equation cannot be solved because is undefined.
Undefined
Step 6.4.2.3
There is no solution for
No solution
No solution
No solution
Step 6.5
Set equal to and solve for .
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Step 6.5.1
Set equal to .
Step 6.5.2
Solve for .
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Step 6.5.2.1
Add to both sides of the equation.
Step 6.5.2.2
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 6.5.2.3
The complete solution is the result of both the positive and negative portions of the solution.
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Step 6.5.2.3.1
First, use the positive value of the to find the first solution.
Step 6.5.2.3.2
Next, use the negative value of the to find the second solution.
Step 6.5.2.3.3
The complete solution is the result of both the positive and negative portions of the solution.
Step 6.6
The final solution is all the values that make true.
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
Rewrite as .
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Step 10.1.1
Use to rewrite as .
Step 10.1.2
Apply the power rule and multiply exponents, .
Step 10.1.3
Combine and .
Step 10.1.4
Cancel the common factor of .
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Step 10.1.4.1
Cancel the common factor.
Step 10.1.4.2
Rewrite the expression.
Step 10.1.5
Evaluate the exponent.
Step 10.2
Simplify by adding terms.
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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
Rewrite as .
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Step 12.2.1.1
Use to rewrite as .
Step 12.2.1.2
Apply the power rule and multiply exponents, .
Step 12.2.1.3
Combine and .
Step 12.2.1.4
Cancel the common factor of .
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Step 12.2.1.4.1
Cancel the common factor.
Step 12.2.1.4.2
Rewrite the expression.
Step 12.2.1.5
Evaluate the exponent.
Step 12.2.2
Apply the distributive property.
Step 12.2.3
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
Simplify each term.
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Step 14.1.1
Apply the product rule to .
Step 14.1.2
Raise to the power of .
Step 14.1.3
Multiply by .
Step 14.1.4
Rewrite as .
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Step 14.1.4.1
Use to rewrite as .
Step 14.1.4.2
Apply the power rule and multiply exponents, .
Step 14.1.4.3
Combine and .
Step 14.1.4.4
Cancel the common factor of .
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Step 14.1.4.4.1
Cancel the common factor.
Step 14.1.4.4.2
Rewrite the expression.
Step 14.1.4.5
Evaluate the exponent.
Step 14.1.5
Multiply by .
Step 14.2
Simplify by adding terms.
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Step 14.2.1
Subtract from .
Step 14.2.2
Add and .
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
Multiply by .
Step 16.2.1.4
Rewrite as .
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Step 16.2.1.4.1
Use to rewrite as .
Step 16.2.1.4.2
Apply the power rule and multiply exponents, .
Step 16.2.1.4.3
Combine and .
Step 16.2.1.4.4
Cancel the common factor of .
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Step 16.2.1.4.4.1
Cancel the common factor.
Step 16.2.1.4.4.2
Rewrite the expression.
Step 16.2.1.4.5
Evaluate the exponent.
Step 16.2.1.5
Multiply by .
Step 16.2.2
Apply the distributive property.
Step 16.2.3
The final answer is .
Step 17
These are the local extrema for .
is a local minima
is a local maxima
Step 18