Calculus Examples

Find the Horizontal Tangent Line xy^2+x^2y=6
Step 1
Solve the equation as in terms of .
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Step 1.1
Subtract from both sides of the equation.
Step 1.2
Use the quadratic formula to find the solutions.
Step 1.3
Substitute the values , , and into the quadratic formula and solve for .
Step 1.4
Simplify the numerator.
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Step 1.4.1
Multiply the exponents in .
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Step 1.4.1.1
Apply the power rule and multiply exponents, .
Step 1.4.1.2
Multiply by .
Step 1.4.2
Multiply by .
Step 1.4.3
Factor out of .
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Step 1.4.3.1
Factor out of .
Step 1.4.3.2
Factor out of .
Step 1.4.3.3
Factor out of .
Step 1.5
Simplify the expression to solve for the portion of the .
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Step 1.5.1
Change the to .
Step 1.5.2
Factor out of .
Step 1.5.3
Factor out of .
Step 1.5.4
Factor out of .
Step 1.5.5
Rewrite as .
Step 1.5.6
Move the negative in front of the fraction.
Step 1.6
Simplify the expression to solve for the portion of the .
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Step 1.6.1
Simplify the numerator.
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Step 1.6.1.1
Multiply the exponents in .
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Step 1.6.1.1.1
Apply the power rule and multiply exponents, .
Step 1.6.1.1.2
Multiply by .
Step 1.6.1.2
Multiply by .
Step 1.6.1.3
Factor out of .
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Step 1.6.1.3.1
Factor out of .
Step 1.6.1.3.2
Factor out of .
Step 1.6.1.3.3
Factor out of .
Step 1.6.2
Change the to .
Step 1.6.3
Factor out of .
Step 1.6.4
Factor out of .
Step 1.6.5
Factor out of .
Step 1.6.6
Rewrite as .
Step 1.6.7
Move the negative in front of the fraction.
Step 1.7
The final answer is the combination of both solutions.
Step 2
Set each solution of as a function of .
Step 3
Because the variable in the equation has a degree greater than , use implicit differentiation to solve for the derivative .
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Step 3.1
Differentiate both sides of the equation.
Step 3.2
Differentiate the left side of the equation.
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Step 3.2.1
By the Sum Rule, the derivative of with respect to is .
Step 3.2.2
Evaluate .
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Step 3.2.2.1
Differentiate using the Product Rule which states that is where and .
Step 3.2.2.2
Differentiate using the chain rule, which states that is where and .
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Step 3.2.2.2.1
To apply the Chain Rule, set as .
Step 3.2.2.2.2
Differentiate using the Power Rule which states that is where .
Step 3.2.2.2.3
Replace all occurrences of with .
Step 3.2.2.3
Rewrite as .
Step 3.2.2.4
Differentiate using the Power Rule which states that is where .
Step 3.2.2.5
Move to the left of .
Step 3.2.2.6
Multiply by .
Step 3.2.3
Evaluate .
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Step 3.2.3.1
Differentiate using the Product Rule which states that is where and .
Step 3.2.3.2
Rewrite as .
Step 3.2.3.3
Differentiate using the Power Rule which states that is where .
Step 3.2.3.4
Move to the left of .
Step 3.2.4
Reorder terms.
Step 3.3
Since is constant with respect to , the derivative of with respect to is .
Step 3.4
Reform the equation by setting the left side equal to the right side.
Step 3.5
Solve for .
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Step 3.5.1
Move all terms not containing to the right side of the equation.
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Step 3.5.1.1
Subtract from both sides of the equation.
Step 3.5.1.2
Subtract from both sides of the equation.
Step 3.5.2
Factor out of .
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Step 3.5.2.1
Factor out of .
Step 3.5.2.2
Factor out of .
Step 3.5.2.3
Factor out of .
Step 3.5.3
Divide each term in by and simplify.
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Step 3.5.3.1
Divide each term in by .
Step 3.5.3.2
Simplify the left side.
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Step 3.5.3.2.1
Cancel the common factor of .
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Step 3.5.3.2.1.1
Cancel the common factor.
Step 3.5.3.2.1.2
Rewrite the expression.
Step 3.5.3.2.2
Cancel the common factor of .
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Step 3.5.3.2.2.1
Cancel the common factor.
Step 3.5.3.2.2.2
Divide by .
Step 3.5.3.3
Simplify the right side.
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Step 3.5.3.3.1
Simplify each term.
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Step 3.5.3.3.1.1
Move the negative in front of the fraction.
Step 3.5.3.3.1.2
Cancel the common factor of .
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Step 3.5.3.3.1.2.1
Cancel the common factor.
Step 3.5.3.3.1.2.2
Rewrite the expression.
Step 3.5.3.3.1.3
Move the negative in front of the fraction.
Step 3.5.3.3.2
To write as a fraction with a common denominator, multiply by .
Step 3.5.3.3.3
Write each expression with a common denominator of , by multiplying each by an appropriate factor of .
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Step 3.5.3.3.3.1
Multiply by .
Step 3.5.3.3.3.2
Reorder the factors of .
Step 3.5.3.3.4
Combine the numerators over the common denominator.
Step 3.5.3.3.5
Factor out of .
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Step 3.5.3.3.5.1
Factor out of .
Step 3.5.3.3.5.2
Factor out of .
Step 3.5.3.3.5.3
Factor out of .
Step 3.5.3.3.6
Factor out of .
Step 3.5.3.3.7
Factor out of .
Step 3.5.3.3.8
Factor out of .
Step 3.5.3.3.9
Simplify the expression.
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Step 3.5.3.3.9.1
Rewrite as .
Step 3.5.3.3.9.2
Move the negative in front of the fraction.
Step 3.6
Replace with .
Step 4
Set the derivative equal to then solve the equation .
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Step 4.1
Set the numerator equal to zero.
Step 4.2
Solve the equation for .
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Step 4.2.1
Divide each term in by and simplify.
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Step 4.2.1.1
Divide each term in by .
Step 4.2.1.2
Simplify the left side.
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Step 4.2.1.2.1
Cancel the common factor of .
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Step 4.2.1.2.1.1
Cancel the common factor.
Step 4.2.1.2.1.2
Divide by .
Step 4.2.1.3
Simplify the right side.
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Step 4.2.1.3.1
Divide by .
Step 4.2.2
Subtract from both sides of the equation.
Step 4.2.3
Divide each term in by and simplify.
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Step 4.2.3.1
Divide each term in by .
Step 4.2.3.2
Simplify the left side.
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Step 4.2.3.2.1
Cancel the common factor of .
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Step 4.2.3.2.1.1
Cancel the common factor.
Step 4.2.3.2.1.2
Divide by .
Step 4.2.3.3
Simplify the right side.
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Step 4.2.3.3.1
Move the negative in front of the fraction.
Step 5
Solve the function at .
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Step 5.1
Replace the variable with in the expression.
Step 5.2
Simplify the result.
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Step 5.2.1
Simplify the numerator.
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Step 5.2.1.1
Use the power rule to distribute the exponent.
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Step 5.2.1.1.1
Apply the product rule to .
Step 5.2.1.1.2
Apply the product rule to .
Step 5.2.1.2
Raise to the power of .
Step 5.2.1.3
Multiply by .
Step 5.2.1.4
Raise to the power of .
Step 5.2.1.5
Use the power rule to distribute the exponent.
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Step 5.2.1.5.1
Apply the product rule to .
Step 5.2.1.5.2
Apply the product rule to .
Step 5.2.1.6
Raise to the power of .
Step 5.2.1.7
Raise to the power of .
Step 5.2.1.8
To write as a fraction with a common denominator, multiply by .
Step 5.2.1.9
Combine and .
Step 5.2.1.10
Combine the numerators over the common denominator.
Step 5.2.1.11
Multiply by .
Step 5.2.1.12
Combine exponents.
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Step 5.2.1.12.1
Multiply by .
Step 5.2.1.12.2
Multiply by .
Step 5.2.1.13
Rewrite as .
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Step 5.2.1.13.1
Factor the perfect power out of .
Step 5.2.1.13.2
Factor the perfect power out of .
Step 5.2.1.13.3
Rearrange the fraction .
Step 5.2.1.13.4
Reorder and .
Step 5.2.1.13.5
Rewrite as .
Step 5.2.1.13.6
Rewrite as .
Step 5.2.1.13.7
Rewrite as .
Step 5.2.1.13.8
Add parentheses.
Step 5.2.1.13.9
Add parentheses.
Step 5.2.1.14
Pull terms out from under the radical.
Step 5.2.1.15
Apply the product rule to .
Step 5.2.1.16
One to any power is one.
Step 5.2.1.17
Raise to the power of .
Step 5.2.1.18
Combine and .
Step 5.2.1.19
Combine the numerators over the common denominator.
Step 5.2.2
Simplify the denominator.
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Step 5.2.2.1
Multiply by .
Step 5.2.2.2
Combine and .
Step 5.2.3
Reduce the expression by cancelling the common factors.
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Step 5.2.3.1
Reduce the expression by cancelling the common factors.
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Step 5.2.3.1.1
Factor out of .
Step 5.2.3.1.2
Factor out of .
Step 5.2.3.1.3
Cancel the common factor.
Step 5.2.3.1.4
Rewrite the expression.
Step 5.2.3.2
Divide by .
Step 5.2.4
Multiply the numerator by the reciprocal of the denominator.
Step 5.2.5
Cancel the common factor of and .
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Step 5.2.5.1
Rewrite as .
Step 5.2.5.2
Move the negative in front of the fraction.
Step 5.2.6
Rewrite using the commutative property of multiplication.
Step 5.2.7
Multiply by .
Step 5.2.8
Move to the left of .
Step 5.2.9
Multiply .
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Step 5.2.9.1
Multiply by .
Step 5.2.9.2
Multiply by .
Step 5.2.10
Reorder factors in .
Step 5.2.11
The final answer is .
Step 6
Solve the function at .
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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
Use the power rule to distribute the exponent.
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Step 6.2.1.1.1
Apply the product rule to .
Step 6.2.1.1.2
Apply the product rule to .
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
Use the power rule to distribute the exponent.
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Step 6.2.1.5.1
Apply the product rule to .
Step 6.2.1.5.2
Apply the product rule to .
Step 6.2.1.6
Raise to the power of .
Step 6.2.1.7
Raise to the power of .
Step 6.2.1.8
To write as a fraction with a common denominator, multiply by .
Step 6.2.1.9
Combine and .
Step 6.2.1.10
Combine the numerators over the common denominator.
Step 6.2.1.11
Multiply by .
Step 6.2.1.12
Combine exponents.
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Step 6.2.1.12.1
Multiply by .
Step 6.2.1.12.2
Multiply by .
Step 6.2.1.13
Rewrite as .
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Step 6.2.1.13.1
Factor the perfect power out of .
Step 6.2.1.13.2
Factor the perfect power out of .
Step 6.2.1.13.3
Rearrange the fraction .
Step 6.2.1.13.4
Reorder and .
Step 6.2.1.13.5
Rewrite as .
Step 6.2.1.13.6
Rewrite as .
Step 6.2.1.13.7
Rewrite as .
Step 6.2.1.13.8
Add parentheses.
Step 6.2.1.13.9
Add parentheses.
Step 6.2.1.14
Pull terms out from under the radical.
Step 6.2.1.15
Apply the product rule to .
Step 6.2.1.16
One to any power is one.
Step 6.2.1.17
Raise to the power of .
Step 6.2.1.18
Combine and .
Step 6.2.1.19
Combine the numerators over the common denominator.
Step 6.2.2
Simplify the denominator.
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Step 6.2.2.1
Multiply by .
Step 6.2.2.2
Combine and .
Step 6.2.3
Reduce the expression by cancelling the common factors.
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Step 6.2.3.1
Reduce the expression by cancelling the common factors.
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Step 6.2.3.1.1
Factor out of .
Step 6.2.3.1.2
Factor out of .
Step 6.2.3.1.3
Cancel the common factor.
Step 6.2.3.1.4
Rewrite the expression.
Step 6.2.3.2
Divide by .
Step 6.2.4
Multiply the numerator by the reciprocal of the denominator.
Step 6.2.5
Cancel the common factor of and .
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Step 6.2.5.1
Rewrite as .
Step 6.2.5.2
Move the negative in front of the fraction.
Step 6.2.6
Rewrite using the commutative property of multiplication.
Step 6.2.7
Multiply by .
Step 6.2.8
Move to the left of .
Step 6.2.9
Multiply .
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Step 6.2.9.1
Multiply by .
Step 6.2.9.2
Multiply by .
Step 6.2.10
Reorder factors in .
Step 6.2.11
The final answer is .
Step 7
The horizontal tangent lines are
Step 8