Calculus Examples

Find Where Increasing/Decreasing Using Derivatives -(2x)/((x^2+1)^2)
Step 1
Write as a function.
Step 2
Find the first derivative.
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Step 2.1
Find the first derivative.
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Step 2.1.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.2
Differentiate using the Quotient Rule which states that is where and .
Step 2.1.3
Differentiate using the Power Rule.
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Step 2.1.3.1
Multiply the exponents in .
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Step 2.1.3.1.1
Apply the power rule and multiply exponents, .
Step 2.1.3.1.2
Multiply by .
Step 2.1.3.2
Differentiate using the Power Rule which states that is where .
Step 2.1.3.3
Multiply by .
Step 2.1.4
Differentiate using the chain rule, which states that is where and .
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Step 2.1.4.1
To apply the Chain Rule, set as .
Step 2.1.4.2
Differentiate using the Power Rule which states that is where .
Step 2.1.4.3
Replace all occurrences of with .
Step 2.1.5
Simplify with factoring out.
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Step 2.1.5.1
Multiply by .
Step 2.1.5.2
Factor out of .
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Step 2.1.5.2.1
Factor out of .
Step 2.1.5.2.2
Factor out of .
Step 2.1.5.2.3
Factor out of .
Step 2.1.6
Cancel the common factors.
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Step 2.1.6.1
Factor out of .
Step 2.1.6.2
Cancel the common factor.
Step 2.1.6.3
Rewrite the expression.
Step 2.1.7
By the Sum Rule, the derivative of with respect to is .
Step 2.1.8
Differentiate using the Power Rule which states that is where .
Step 2.1.9
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.10
Simplify the expression.
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Step 2.1.10.1
Add and .
Step 2.1.10.2
Multiply by .
Step 2.1.11
Raise to the power of .
Step 2.1.12
Raise to the power of .
Step 2.1.13
Use the power rule to combine exponents.
Step 2.1.14
Add and .
Step 2.1.15
Subtract from .
Step 2.1.16
Combine and .
Step 2.1.17
Move the negative in front of the fraction.
Step 2.1.18
Simplify.
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Step 2.1.18.1
Apply the distributive property.
Step 2.1.18.2
Simplify each term.
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Step 2.1.18.2.1
Multiply by .
Step 2.1.18.2.2
Multiply by .
Step 2.1.18.3
Factor out of .
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Step 2.1.18.3.1
Factor out of .
Step 2.1.18.3.2
Factor out of .
Step 2.1.18.3.3
Factor out of .
Step 2.1.18.4
Factor out of .
Step 2.1.18.5
Rewrite as .
Step 2.1.18.6
Factor out of .
Step 2.1.18.7
Rewrite as .
Step 2.1.18.8
Move the negative in front of the fraction.
Step 2.1.18.9
Multiply by .
Step 2.1.18.10
Multiply by .
Step 2.2
The first derivative of with respect to is .
Step 3
Set the first derivative equal to then solve the equation .
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Step 3.1
Set the first derivative equal to .
Step 3.2
Set the numerator equal to zero.
Step 3.3
Solve the equation for .
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Step 3.3.1
Divide each term in by and simplify.
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Step 3.3.1.1
Divide each term in by .
Step 3.3.1.2
Simplify the left side.
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Step 3.3.1.2.1
Cancel the common factor of .
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Step 3.3.1.2.1.1
Cancel the common factor.
Step 3.3.1.2.1.2
Divide by .
Step 3.3.1.3
Simplify the right side.
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Step 3.3.1.3.1
Divide by .
Step 3.3.2
Add to both sides of the equation.
Step 3.3.3
Divide each term in by and simplify.
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Step 3.3.3.1
Divide each term in by .
Step 3.3.3.2
Simplify the left side.
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Step 3.3.3.2.1
Cancel the common factor of .
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Step 3.3.3.2.1.1
Cancel the common factor.
Step 3.3.3.2.1.2
Divide by .
Step 3.3.4
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 3.3.5
Simplify .
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Step 3.3.5.1
Rewrite as .
Step 3.3.5.2
Any root of is .
Step 3.3.5.3
Multiply by .
Step 3.3.5.4
Combine and simplify the denominator.
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Step 3.3.5.4.1
Multiply by .
Step 3.3.5.4.2
Raise to the power of .
Step 3.3.5.4.3
Raise to the power of .
Step 3.3.5.4.4
Use the power rule to combine exponents.
Step 3.3.5.4.5
Add and .
Step 3.3.5.4.6
Rewrite as .
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Step 3.3.5.4.6.1
Use to rewrite as .
Step 3.3.5.4.6.2
Apply the power rule and multiply exponents, .
Step 3.3.5.4.6.3
Combine and .
Step 3.3.5.4.6.4
Cancel the common factor of .
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Step 3.3.5.4.6.4.1
Cancel the common factor.
Step 3.3.5.4.6.4.2
Rewrite the expression.
Step 3.3.5.4.6.5
Evaluate the exponent.
Step 3.3.6
The complete solution is the result of both the positive and negative portions of the solution.
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Step 3.3.6.1
First, use the positive value of the to find the first solution.
Step 3.3.6.2
Next, use the negative value of the to find the second solution.
Step 3.3.6.3
The complete solution is the result of both the positive and negative portions of the solution.
Step 4
The values which make the derivative equal to are .
Step 5
Split into separate intervals around the values that make the derivative or undefined.
Step 6
Substitute a value from the interval into the derivative to determine if the function is increasing or decreasing.
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Step 6.1
Replace the variable with in the expression.
Step 6.2
Simplify the result.
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Step 6.2.1
Simplify the numerator.
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Step 6.2.1.1
Raise to the power of .
Step 6.2.1.2
Multiply by .
Step 6.2.1.3
Subtract from .
Step 6.2.2
Simplify the denominator.
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Step 6.2.2.1
Raise to the power of .
Step 6.2.2.2
Add and .
Step 6.2.2.3
Raise to the power of .
Step 6.2.3
Simplify the expression.
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Step 6.2.3.1
Multiply by .
Step 6.2.3.2
Divide by .
Step 6.2.4
The final answer is .
Step 6.3
At the derivative is . Since this is positive, the function is increasing on .
Increasing on since
Increasing on since
Step 7
Substitute a value from the interval into the derivative to determine if the function is increasing or decreasing.
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Step 7.1
Replace the variable with in the expression.
Step 7.2
Simplify the result.
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Step 7.2.1
Simplify the numerator.
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Step 7.2.1.1
Raising to any positive power yields .
Step 7.2.1.2
Multiply by .
Step 7.2.1.3
Subtract from .
Step 7.2.2
Simplify the denominator.
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Step 7.2.2.1
Raising to any positive power yields .
Step 7.2.2.2
Add and .
Step 7.2.2.3
One to any power is one.
Step 7.2.3
Simplify the expression.
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Step 7.2.3.1
Multiply by .
Step 7.2.3.2
Divide by .
Step 7.2.4
The final answer is .
Step 7.3
At the derivative is . Since this is negative, the function is decreasing on .
Decreasing on since
Decreasing on since
Step 8
Substitute a value from the interval into the derivative to determine if the function is increasing or decreasing.
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Step 8.1
Replace the variable with in the expression.
Step 8.2
Simplify the result.
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Step 8.2.1
Simplify the numerator.
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Step 8.2.1.1
Raise to the power of .
Step 8.2.1.2
Multiply by .
Step 8.2.1.3
Subtract from .
Step 8.2.2
Simplify the denominator.
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Step 8.2.2.1
Raise to the power of .
Step 8.2.2.2
Add and .
Step 8.2.2.3
Raise to the power of .
Step 8.2.3
Simplify the expression.
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Step 8.2.3.1
Multiply by .
Step 8.2.3.2
Divide by .
Step 8.2.4
The final answer is .
Step 8.3
At the derivative is . Since this is positive, the function is increasing on .
Increasing on since
Increasing on since
Step 9
List the intervals on which the function is increasing and decreasing.
Increasing on:
Decreasing on:
Step 10