Calculus Examples

Find the Horizontal Tangent Line x^2+xy+y^2=3
Step 1
Solve the equation as in terms of .
Tap for more steps...
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.
Tap for more steps...
Step 1.4.1
Simplify the numerator.
Tap for more steps...
Step 1.4.1.1
Multiply by .
Step 1.4.1.2
Apply the distributive property.
Step 1.4.1.3
Multiply by .
Step 1.4.1.4
Subtract from .
Step 1.4.1.5
Rewrite in a factored form.
Tap for more steps...
Step 1.4.1.5.1
Factor out of .
Tap for more steps...
Step 1.4.1.5.1.1
Factor out of .
Step 1.4.1.5.1.2
Factor out of .
Step 1.4.1.5.1.3
Factor out of .
Step 1.4.1.5.2
Rewrite as .
Step 1.4.1.5.3
Reorder and .
Step 1.4.1.5.4
Since both terms are perfect squares, factor using the difference of squares formula, where and .
Step 1.4.2
Multiply by .
Step 1.5
Simplify the expression to solve for the portion of the .
Tap for more steps...
Step 1.5.1
Simplify the numerator.
Tap for more steps...
Step 1.5.1.1
Multiply by .
Step 1.5.1.2
Apply the distributive property.
Step 1.5.1.3
Multiply by .
Step 1.5.1.4
Subtract from .
Step 1.5.1.5
Rewrite in a factored form.
Tap for more steps...
Step 1.5.1.5.1
Factor out of .
Tap for more steps...
Step 1.5.1.5.1.1
Factor out of .
Step 1.5.1.5.1.2
Factor out of .
Step 1.5.1.5.1.3
Factor out of .
Step 1.5.1.5.2
Rewrite as .
Step 1.5.1.5.3
Reorder and .
Step 1.5.1.5.4
Since both terms are perfect squares, factor using the difference of squares formula, where and .
Step 1.5.2
Multiply by .
Step 1.5.3
Change the to .
Step 1.5.4
Factor out of .
Step 1.5.5
Factor out of .
Step 1.5.6
Factor out of .
Step 1.5.7
Rewrite as .
Step 1.5.8
Move the negative in front of the fraction.
Step 1.6
Simplify the expression to solve for the portion of the .
Tap for more steps...
Step 1.6.1
Simplify the numerator.
Tap for more steps...
Step 1.6.1.1
Multiply by .
Step 1.6.1.2
Apply the distributive property.
Step 1.6.1.3
Multiply by .
Step 1.6.1.4
Subtract from .
Step 1.6.1.5
Rewrite in a factored form.
Tap for more steps...
Step 1.6.1.5.1
Factor out of .
Tap for more steps...
Step 1.6.1.5.1.1
Factor out of .
Step 1.6.1.5.1.2
Factor out of .
Step 1.6.1.5.1.3
Factor out of .
Step 1.6.1.5.2
Rewrite as .
Step 1.6.1.5.3
Reorder and .
Step 1.6.1.5.4
Since both terms are perfect squares, factor using the difference of squares formula, where and .
Step 1.6.2
Multiply by .
Step 1.6.3
Change the to .
Step 1.6.4
Factor out of .
Step 1.6.5
Factor out of .
Step 1.6.6
Factor out of .
Step 1.6.7
Rewrite as .
Step 1.6.8
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 .
Tap for more steps...
Step 3.1
Differentiate both sides of the equation.
Step 3.2
Differentiate the left side of the equation.
Tap for more steps...
Step 3.2.1
Differentiate.
Tap for more steps...
Step 3.2.1.1
By the Sum Rule, the derivative of with respect to is .
Step 3.2.1.2
Differentiate using the Power Rule which states that is where .
Step 3.2.2
Evaluate .
Tap for more steps...
Step 3.2.2.1
Differentiate using the Product Rule which states that is where and .
Step 3.2.2.2
Rewrite as .
Step 3.2.2.3
Differentiate using the Power Rule which states that is where .
Step 3.2.2.4
Multiply by .
Step 3.2.3
Evaluate .
Tap for more steps...
Step 3.2.3.1
Differentiate using the chain rule, which states that is where and .
Tap for more steps...
Step 3.2.3.1.1
To apply the Chain Rule, set as .
Step 3.2.3.1.2
Differentiate using the Power Rule which states that is where .
Step 3.2.3.1.3
Replace all occurrences of with .
Step 3.2.3.2
Rewrite as .
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 .
Tap for more steps...
Step 3.5.1
Move all terms not containing to the right side of the equation.
Tap for more steps...
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 .
Tap for more steps...
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.
Tap for more steps...
Step 3.5.3.1
Divide each term in by .
Step 3.5.3.2
Simplify the left side.
Tap for more steps...
Step 3.5.3.2.1
Cancel the common factor of .
Tap for more steps...
Step 3.5.3.2.1.1
Cancel the common factor.
Step 3.5.3.2.1.2
Divide by .
Step 3.5.3.3
Simplify the right side.
Tap for more steps...
Step 3.5.3.3.1
Combine the numerators over the common denominator.
Step 3.5.3.3.2
Factor out of .
Step 3.5.3.3.3
Factor out of .
Step 3.5.3.3.4
Factor out of .
Step 3.5.3.3.5
Simplify the expression.
Tap for more steps...
Step 3.5.3.3.5.1
Rewrite as .
Step 3.5.3.3.5.2
Move the negative in front of the fraction.
Step 3.6
Replace with .
Step 4
Set the derivative equal to then solve the equation .
Tap for more steps...
Step 4.1
Set the numerator equal to zero.
Step 4.2
Solve the equation for .
Tap for more steps...
Step 4.2.1
Subtract from both sides of the equation.
Step 4.2.2
Divide each term in by and simplify.
Tap for more steps...
Step 4.2.2.1
Divide each term in by .
Step 4.2.2.2
Simplify the left side.
Tap for more steps...
Step 4.2.2.2.1
Cancel the common factor of .
Tap for more steps...
Step 4.2.2.2.1.1
Cancel the common factor.
Step 4.2.2.2.1.2
Divide by .
Step 4.2.2.3
Simplify the right side.
Tap for more steps...
Step 4.2.2.3.1
Move the negative in front of the fraction.
Step 5
Solve the function at .
Tap for more steps...
Step 5.1
Replace the variable with in the expression.
Step 5.2
Simplify the result.
Tap for more steps...
Step 5.2.1
Remove parentheses.
Step 5.2.2
Simplify the numerator.
Tap for more steps...
Step 5.2.2.1
Combine exponents.
Tap for more steps...
Step 5.2.2.1.1
Multiply by .
Step 5.2.2.1.2
Multiply by .
Step 5.2.2.2
To write as a fraction with a common denominator, multiply by .
Step 5.2.2.3
Combine and .
Step 5.2.2.4
Combine the numerators over the common denominator.
Step 5.2.2.5
Multiply by .
Step 5.2.2.6
To write as a fraction with a common denominator, multiply by .
Step 5.2.2.7
Combine and .
Step 5.2.2.8
Combine the numerators over the common denominator.
Step 5.2.2.9
Multiply by .
Step 5.2.2.10
Combine exponents.
Tap for more steps...
Step 5.2.2.10.1
Combine and .
Step 5.2.2.10.2
Multiply by .
Step 5.2.2.10.3
Multiply by .
Step 5.2.2.11
Rewrite as .
Tap for more steps...
Step 5.2.2.11.1
Factor the perfect power out of .
Step 5.2.2.11.2
Factor the perfect power out of .
Step 5.2.2.11.3
Rearrange the fraction .
Step 5.2.2.12
Pull terms out from under the radical.
Step 5.2.2.13
Combine and .
Step 5.2.2.14
Combine the numerators over the common denominator.
Step 5.2.3
Multiply the numerator by the reciprocal of the denominator.
Step 5.2.4
Multiply .
Tap for more steps...
Step 5.2.4.1
Multiply by .
Step 5.2.4.2
Multiply by .
Step 5.2.5
Factor out of .
Step 5.2.6
Factor out of .
Step 5.2.7
Factor out of .
Step 5.2.8
Simplify the expression.
Tap for more steps...
Step 5.2.8.1
Rewrite as .
Step 5.2.8.2
Move the negative in front of the fraction.
Step 5.2.8.3
Multiply by .
Step 5.2.8.4
Multiply by .
Step 5.2.9
The final answer is .
Step 6
Solve the function at .
Tap for more steps...
Step 6.1
Replace the variable with in the expression.
Step 6.2
Simplify the result.
Tap for more steps...
Step 6.2.1
Remove parentheses.
Step 6.2.2
Simplify the numerator.
Tap for more steps...
Step 6.2.2.1
Combine exponents.
Tap for more steps...
Step 6.2.2.1.1
Multiply by .
Step 6.2.2.1.2
Multiply by .
Step 6.2.2.2
To write as a fraction with a common denominator, multiply by .
Step 6.2.2.3
Combine and .
Step 6.2.2.4
Combine the numerators over the common denominator.
Step 6.2.2.5
Multiply by .
Step 6.2.2.6
To write as a fraction with a common denominator, multiply by .
Step 6.2.2.7
Combine and .
Step 6.2.2.8
Combine the numerators over the common denominator.
Step 6.2.2.9
Multiply by .
Step 6.2.2.10
Combine exponents.
Tap for more steps...
Step 6.2.2.10.1
Combine and .
Step 6.2.2.10.2
Multiply by .
Step 6.2.2.10.3
Multiply by .
Step 6.2.2.11
Rewrite as .
Tap for more steps...
Step 6.2.2.11.1
Factor the perfect power out of .
Step 6.2.2.11.2
Factor the perfect power out of .
Step 6.2.2.11.3
Rearrange the fraction .
Step 6.2.2.12
Pull terms out from under the radical.
Step 6.2.2.13
Combine and .
Step 6.2.2.14
Combine the numerators over the common denominator.
Step 6.2.3
Multiply the numerator by the reciprocal of the denominator.
Step 6.2.4
Multiply .
Tap for more steps...
Step 6.2.4.1
Multiply by .
Step 6.2.4.2
Multiply by .
Step 6.2.5
Factor out of .
Step 6.2.6
Factor out of .
Step 6.2.7
Factor out of .
Step 6.2.8
Simplify the expression.
Tap for more steps...
Step 6.2.8.1
Rewrite as .
Step 6.2.8.2
Move the negative in front of the fraction.
Step 6.2.8.3
Multiply by .
Step 6.2.8.4
Multiply by .
Step 6.2.9
The final answer is .
Step 7
The horizontal tangent lines are
Step 8