Calculus Examples

Find Where Increasing/Decreasing Using Derivatives 1/5x^5+7/2x^4+71/3x^3+77x^2+120x
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
By the Sum Rule, the derivative of with respect to is .
Step 2.1.2
Evaluate .
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Step 2.1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.2.2
Differentiate using the Power Rule which states that is where .
Step 2.1.2.3
Combine and .
Step 2.1.2.4
Combine and .
Step 2.1.2.5
Cancel the common factor of .
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Step 2.1.2.5.1
Cancel the common factor.
Step 2.1.2.5.2
Divide by .
Step 2.1.3
Evaluate .
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Step 2.1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.3.2
Differentiate using the Power Rule which states that is where .
Step 2.1.3.3
Combine and .
Step 2.1.3.4
Multiply by .
Step 2.1.3.5
Combine and .
Step 2.1.3.6
Cancel the common factor of and .
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Step 2.1.3.6.1
Factor out of .
Step 2.1.3.6.2
Cancel the common factors.
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Step 2.1.3.6.2.1
Factor out of .
Step 2.1.3.6.2.2
Cancel the common factor.
Step 2.1.3.6.2.3
Rewrite the expression.
Step 2.1.3.6.2.4
Divide by .
Step 2.1.4
Evaluate .
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Step 2.1.4.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.4.2
Differentiate using the Power Rule which states that is where .
Step 2.1.4.3
Combine and .
Step 2.1.4.4
Multiply by .
Step 2.1.4.5
Combine and .
Step 2.1.4.6
Cancel the common factor of and .
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Step 2.1.4.6.1
Factor out of .
Step 2.1.4.6.2
Cancel the common factors.
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Step 2.1.4.6.2.1
Factor out of .
Step 2.1.4.6.2.2
Cancel the common factor.
Step 2.1.4.6.2.3
Rewrite the expression.
Step 2.1.4.6.2.4
Divide by .
Step 2.1.5
Evaluate .
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Step 2.1.5.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.5.2
Differentiate using the Power Rule which states that is where .
Step 2.1.5.3
Multiply by .
Step 2.1.6
Evaluate .
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Step 2.1.6.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.1.6.2
Differentiate using the Power Rule which states that is where .
Step 2.1.6.3
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
Factor the left side of the equation.
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Step 3.2.1
Factor using the rational roots test.
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Step 3.2.1.1
If a polynomial function has integer coefficients, then every rational zero will have the form where is a factor of the constant and is a factor of the leading coefficient.
Step 3.2.1.2
Find every combination of . These are the possible roots of the polynomial function.
Step 3.2.1.3
Substitute and simplify the expression. In this case, the expression is equal to so is a root of the polynomial.
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Step 3.2.1.3.1
Substitute into the polynomial.
Step 3.2.1.3.2
Raise to the power of .
Step 3.2.1.3.3
Raise to the power of .
Step 3.2.1.3.4
Multiply by .
Step 3.2.1.3.5
Subtract from .
Step 3.2.1.3.6
Raise to the power of .
Step 3.2.1.3.7
Multiply by .
Step 3.2.1.3.8
Add and .
Step 3.2.1.3.9
Multiply by .
Step 3.2.1.3.10
Subtract from .
Step 3.2.1.3.11
Add and .
Step 3.2.1.4
Since is a known root, divide the polynomial by to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
Step 3.2.1.5
Divide by .
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Step 3.2.1.5.1
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of .
+++++
Step 3.2.1.5.2
Divide the highest order term in the dividend by the highest order term in divisor .
+++++
Step 3.2.1.5.3
Multiply the new quotient term by the divisor.
+++++
++
Step 3.2.1.5.4
The expression needs to be subtracted from the dividend, so change all the signs in
+++++
--
Step 3.2.1.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+++++
--
+
Step 3.2.1.5.6
Pull the next terms from the original dividend down into the current dividend.
+++++
--
++
Step 3.2.1.5.7
Divide the highest order term in the dividend by the highest order term in divisor .
+
+++++
--
++
Step 3.2.1.5.8
Multiply the new quotient term by the divisor.
+
+++++
--
++
++
Step 3.2.1.5.9
The expression needs to be subtracted from the dividend, so change all the signs in
+
+++++
--
++
--
Step 3.2.1.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+
+++++
--
++
--
+
Step 3.2.1.5.11
Pull the next terms from the original dividend down into the current dividend.
+
+++++
--
++
--
++
Step 3.2.1.5.12
Divide the highest order term in the dividend by the highest order term in divisor .
++
+++++
--
++
--
++
Step 3.2.1.5.13
Multiply the new quotient term by the divisor.
++
+++++
--
++
--
++
++
Step 3.2.1.5.14
The expression needs to be subtracted from the dividend, so change all the signs in
++
+++++
--
++
--
++
--
Step 3.2.1.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
++
+++++
--
++
--
++
--
+
Step 3.2.1.5.16
Pull the next terms from the original dividend down into the current dividend.
++
+++++
--
++
--
++
--
++
Step 3.2.1.5.17
Divide the highest order term in the dividend by the highest order term in divisor .
+++
+++++
--
++
--
++
--
++
Step 3.2.1.5.18
Multiply the new quotient term by the divisor.
+++
+++++
--
++
--
++
--
++
++
Step 3.2.1.5.19
The expression needs to be subtracted from the dividend, so change all the signs in
+++
+++++
--
++
--
++
--
++
--
Step 3.2.1.5.20
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+++
+++++
--
++
--
++
--
++
--
Step 3.2.1.5.21
Since the remander is , the final answer is the quotient.
Step 3.2.1.6
Write as a set of factors.
Step 3.2.2
Factor using the rational roots test.
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Step 3.2.2.1
If a polynomial function has integer coefficients, then every rational zero will have the form where is a factor of the constant and is a factor of the leading coefficient.
Step 3.2.2.2
Find every combination of . These are the possible roots of the polynomial function.
Step 3.2.2.3
Substitute and simplify the expression. In this case, the expression is equal to so is a root of the polynomial.
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Step 3.2.2.3.1
Substitute into the polynomial.
Step 3.2.2.3.2
Raise to the power of .
Step 3.2.2.3.3
Raise to the power of .
Step 3.2.2.3.4
Multiply by .
Step 3.2.2.3.5
Add and .
Step 3.2.2.3.6
Multiply by .
Step 3.2.2.3.7
Subtract from .
Step 3.2.2.3.8
Add and .
Step 3.2.2.4
Since is a known root, divide the polynomial by to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
Step 3.2.2.5
Divide by .
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Step 3.2.2.5.1
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of .
++++
Step 3.2.2.5.2
Divide the highest order term in the dividend by the highest order term in divisor .
++++
Step 3.2.2.5.3
Multiply the new quotient term by the divisor.
++++
++
Step 3.2.2.5.4
The expression needs to be subtracted from the dividend, so change all the signs in
++++
--
Step 3.2.2.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
++++
--
+
Step 3.2.2.5.6
Pull the next terms from the original dividend down into the current dividend.
++++
--
++
Step 3.2.2.5.7
Divide the highest order term in the dividend by the highest order term in divisor .
+
++++
--
++
Step 3.2.2.5.8
Multiply the new quotient term by the divisor.
+
++++
--
++
++
Step 3.2.2.5.9
The expression needs to be subtracted from the dividend, so change all the signs in
+
++++
--
++
--
Step 3.2.2.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+
++++
--
++
--
+
Step 3.2.2.5.11
Pull the next terms from the original dividend down into the current dividend.
+
++++
--
++
--
++
Step 3.2.2.5.12
Divide the highest order term in the dividend by the highest order term in divisor .
++
++++
--
++
--
++
Step 3.2.2.5.13
Multiply the new quotient term by the divisor.
++
++++
--
++
--
++
++
Step 3.2.2.5.14
The expression needs to be subtracted from the dividend, so change all the signs in
++
++++
--
++
--
++
--
Step 3.2.2.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
++
++++
--
++
--
++
--
Step 3.2.2.5.16
Since the remander is , the final answer is the quotient.
Step 3.2.2.6
Write as a set of factors.
Step 3.2.3
Factor using the AC method.
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Step 3.2.3.1
Factor using the AC method.
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Step 3.2.3.1.1
Factor using the AC method.
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Step 3.2.3.1.1.1
Consider the form . Find a pair of integers whose product is and whose sum is . In this case, whose product is and whose sum is .
Step 3.2.3.1.1.2
Write the factored form using these integers.
Step 3.2.3.1.2
Remove unnecessary parentheses.
Step 3.2.3.2
Remove unnecessary parentheses.
Step 3.3
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 3.4
Set equal to and solve for .
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Step 3.4.1
Set equal to .
Step 3.4.2
Subtract from both sides of the equation.
Step 3.5
Set equal to and solve for .
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Step 3.5.1
Set equal to .
Step 3.5.2
Subtract from both sides of the equation.
Step 3.6
Set equal to and solve for .
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Step 3.6.1
Set equal to .
Step 3.6.2
Subtract from both sides of the equation.
Step 3.7
Set equal to and solve for .
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Step 3.7.1
Set equal to .
Step 3.7.2
Subtract from both sides of the equation.
Step 3.8
The final solution is all the values that make true.
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 each term.
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Step 6.2.1.1
Raise to the power of .
Step 6.2.1.2
Raise to the power of .
Step 6.2.1.3
Multiply by .
Step 6.2.1.4
Raise to the power of .
Step 6.2.1.5
Multiply by .
Step 6.2.1.6
Multiply by .
Step 6.2.2
Simplify by adding and subtracting.
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Step 6.2.2.1
Subtract from .
Step 6.2.2.2
Add and .
Step 6.2.2.3
Subtract from .
Step 6.2.2.4
Add and .
Step 6.2.3
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 each term.
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Step 7.2.1.1
Use the power rule to distribute the exponent.
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Step 7.2.1.1.1
Apply the product rule to .
Step 7.2.1.1.2
Apply the product rule to .
Step 7.2.1.2
Raise to the power of .
Step 7.2.1.3
Multiply by .
Step 7.2.1.4
Raise to the power of .
Step 7.2.1.5
Raise to the power of .
Step 7.2.1.6
Use the power rule to distribute the exponent.
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Step 7.2.1.6.1
Apply the product rule to .
Step 7.2.1.6.2
Apply the product rule to .
Step 7.2.1.7
Raise to the power of .
Step 7.2.1.8
Raise to the power of .
Step 7.2.1.9
Raise to the power of .
Step 7.2.1.10
Cancel the common factor of .
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Step 7.2.1.10.1
Move the leading negative in into the numerator.
Step 7.2.1.10.2
Factor out of .
Step 7.2.1.10.3
Factor out of .
Step 7.2.1.10.4
Cancel the common factor.
Step 7.2.1.10.5
Rewrite the expression.
Step 7.2.1.11
Combine and .
Step 7.2.1.12
Multiply by .
Step 7.2.1.13
Move the negative in front of the fraction.
Step 7.2.1.14
Use the power rule to distribute the exponent.
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Step 7.2.1.14.1
Apply the product rule to .
Step 7.2.1.14.2
Apply the product rule to .
Step 7.2.1.15
Raise to the power of .
Step 7.2.1.16
Multiply by .
Step 7.2.1.17
Raise to the power of .
Step 7.2.1.18
Raise to the power of .
Step 7.2.1.19
Multiply .
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Step 7.2.1.19.1
Combine and .
Step 7.2.1.19.2
Multiply by .
Step 7.2.1.20
Cancel the common factor of .
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Step 7.2.1.20.1
Move the leading negative in into the numerator.
Step 7.2.1.20.2
Factor out of .
Step 7.2.1.20.3
Cancel the common factor.
Step 7.2.1.20.4
Rewrite the expression.
Step 7.2.1.21
Multiply by .
Step 7.2.2
Combine fractions.
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Step 7.2.2.1
Combine the numerators over the common denominator.
Step 7.2.2.2
Add and .
Step 7.2.3
Find the common denominator.
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Step 7.2.3.1
Write as a fraction with denominator .
Step 7.2.3.2
Multiply by .
Step 7.2.3.3
Multiply by .
Step 7.2.3.4
Write as a fraction with denominator .
Step 7.2.3.5
Multiply by .
Step 7.2.3.6
Multiply by .
Step 7.2.3.7
Multiply by .
Step 7.2.3.8
Multiply by .
Step 7.2.3.9
Multiply by .
Step 7.2.4
Combine the numerators over the common denominator.
Step 7.2.5
Simplify each term.
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Step 7.2.5.1
Multiply by .
Step 7.2.5.2
Multiply by .
Step 7.2.5.3
Multiply by .
Step 7.2.6
Simplify the expression.
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Step 7.2.6.1
Add and .
Step 7.2.6.2
Add and .
Step 7.2.6.3
Add and .
Step 7.2.6.4
Move the negative in front of the fraction.
Step 7.2.7
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 each term.
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Step 8.2.1.1
Use the power rule to distribute the exponent.
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Step 8.2.1.1.1
Apply the product rule to .
Step 8.2.1.1.2
Apply the product rule to .
Step 8.2.1.2
Raise to the power of .
Step 8.2.1.3
Multiply by .
Step 8.2.1.4
Raise to the power of .
Step 8.2.1.5
Raise to the power of .
Step 8.2.1.6
Use the power rule to distribute the exponent.
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Step 8.2.1.6.1
Apply the product rule to .
Step 8.2.1.6.2
Apply the product rule to .
Step 8.2.1.7
Raise to the power of .
Step 8.2.1.8
Raise to the power of .
Step 8.2.1.9
Raise to the power of .
Step 8.2.1.10
Cancel the common factor of .
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Step 8.2.1.10.1
Move the leading negative in into the numerator.
Step 8.2.1.10.2
Factor out of .
Step 8.2.1.10.3
Factor out of .
Step 8.2.1.10.4
Cancel the common factor.
Step 8.2.1.10.5
Rewrite the expression.
Step 8.2.1.11
Combine and .
Step 8.2.1.12
Multiply by .
Step 8.2.1.13
Move the negative in front of the fraction.
Step 8.2.1.14
Use the power rule to distribute the exponent.
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Step 8.2.1.14.1
Apply the product rule to .
Step 8.2.1.14.2
Apply the product rule to .
Step 8.2.1.15
Raise to the power of .
Step 8.2.1.16
Multiply by .
Step 8.2.1.17
Raise to the power of .
Step 8.2.1.18
Raise to the power of .
Step 8.2.1.19
Multiply .
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Step 8.2.1.19.1
Combine and .
Step 8.2.1.19.2
Multiply by .
Step 8.2.1.20
Cancel the common factor of .
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Step 8.2.1.20.1
Move the leading negative in into the numerator.
Step 8.2.1.20.2
Factor out of .
Step 8.2.1.20.3
Cancel the common factor.
Step 8.2.1.20.4
Rewrite the expression.
Step 8.2.1.21
Multiply by .
Step 8.2.2
Combine fractions.
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Step 8.2.2.1
Combine the numerators over the common denominator.
Step 8.2.2.2
Add and .
Step 8.2.3
Find the common denominator.
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Step 8.2.3.1
Write as a fraction with denominator .
Step 8.2.3.2
Multiply by .
Step 8.2.3.3
Multiply by .
Step 8.2.3.4
Write as a fraction with denominator .
Step 8.2.3.5
Multiply by .
Step 8.2.3.6
Multiply by .
Step 8.2.3.7
Multiply by .
Step 8.2.3.8
Multiply by .
Step 8.2.3.9
Multiply by .
Step 8.2.4
Combine the numerators over the common denominator.
Step 8.2.5
Simplify each term.
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Step 8.2.5.1
Multiply by .
Step 8.2.5.2
Multiply by .
Step 8.2.5.3
Multiply by .
Step 8.2.6
Simplify by adding numbers.
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Step 8.2.6.1
Add and .
Step 8.2.6.2
Add and .
Step 8.2.6.3
Add and .
Step 8.2.7
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
Substitute a value from the interval into the derivative to determine if the function is increasing or decreasing.
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Step 9.1
Replace the variable with in the expression.
Step 9.2
Simplify the result.
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Step 9.2.1
Simplify each term.
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Step 9.2.1.1
Use the power rule to distribute the exponent.
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Step 9.2.1.1.1
Apply the product rule to .
Step 9.2.1.1.2
Apply the product rule to .
Step 9.2.1.2
Raise to the power of .
Step 9.2.1.3
Multiply by .
Step 9.2.1.4
Raise to the power of .
Step 9.2.1.5
Raise to the power of .
Step 9.2.1.6
Use the power rule to distribute the exponent.
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Step 9.2.1.6.1
Apply the product rule to .
Step 9.2.1.6.2
Apply the product rule to .
Step 9.2.1.7
Raise to the power of .
Step 9.2.1.8
Raise to the power of .
Step 9.2.1.9
Raise to the power of .
Step 9.2.1.10
Cancel the common factor of .
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Step 9.2.1.10.1
Move the leading negative in into the numerator.
Step 9.2.1.10.2
Factor out of .
Step 9.2.1.10.3
Factor out of .
Step 9.2.1.10.4
Cancel the common factor.
Step 9.2.1.10.5
Rewrite the expression.
Step 9.2.1.11
Combine and .
Step 9.2.1.12
Multiply by .
Step 9.2.1.13
Move the negative in front of the fraction.
Step 9.2.1.14
Use the power rule to distribute the exponent.
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Step 9.2.1.14.1
Apply the product rule to .
Step 9.2.1.14.2
Apply the product rule to .
Step 9.2.1.15
Raise to the power of .
Step 9.2.1.16
Multiply by .
Step 9.2.1.17
Raise to the power of .
Step 9.2.1.18
Raise to the power of .
Step 9.2.1.19
Multiply .
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Step 9.2.1.19.1
Combine and .
Step 9.2.1.19.2
Multiply by .
Step 9.2.1.20
Cancel the common factor of .
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Step 9.2.1.20.1
Move the leading negative in into the numerator.
Step 9.2.1.20.2
Factor out of .
Step 9.2.1.20.3
Cancel the common factor.
Step 9.2.1.20.4
Rewrite the expression.
Step 9.2.1.21
Multiply by .
Step 9.2.2
Combine fractions.
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Step 9.2.2.1
Combine the numerators over the common denominator.
Step 9.2.2.2
Add and .
Step 9.2.3
Find the common denominator.
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Step 9.2.3.1
Write as a fraction with denominator .
Step 9.2.3.2
Multiply by .
Step 9.2.3.3
Multiply by .
Step 9.2.3.4
Write as a fraction with denominator .
Step 9.2.3.5
Multiply by .
Step 9.2.3.6
Multiply by .
Step 9.2.3.7
Multiply by .
Step 9.2.3.8
Multiply by .
Step 9.2.3.9
Multiply by .
Step 9.2.4
Combine the numerators over the common denominator.
Step 9.2.5
Simplify each term.
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Step 9.2.5.1
Multiply by .
Step 9.2.5.2
Multiply by .
Step 9.2.5.3
Multiply by .
Step 9.2.6
Simplify the expression.
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Step 9.2.6.1
Add and .
Step 9.2.6.2
Add and .
Step 9.2.6.3
Add and .
Step 9.2.6.4
Move the negative in front of the fraction.
Step 9.2.7
The final answer is .
Step 9.3
At the derivative is . Since this is negative, the function is decreasing on .
Decreasing on since
Decreasing on since
Step 10
Substitute a value from the interval into the derivative to determine if the function is increasing or decreasing.
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Step 10.1
Replace the variable with in the expression.
Step 10.2
Simplify the result.
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Step 10.2.1
Simplify each term.
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Step 10.2.1.1
Raise to the power of .
Step 10.2.1.2
Raise to the power of .
Step 10.2.1.3
Multiply by .
Step 10.2.1.4
Raise to the power of .
Step 10.2.1.5
Multiply by .
Step 10.2.1.6
Multiply by .
Step 10.2.2
Simplify by adding and subtracting.
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Step 10.2.2.1
Subtract from .
Step 10.2.2.2
Add and .
Step 10.2.2.3
Subtract from .
Step 10.2.2.4
Add and .
Step 10.2.3
The final answer is .
Step 10.3
At the derivative is . Since this is positive, the function is increasing on .
Increasing on since
Increasing on since
Step 11
List the intervals on which the function is increasing and decreasing.
Increasing on:
Decreasing on:
Step 12