Calculus Examples

Solve the Differential Equation (dy)/(dx)-y=y^3
Step 1
To solve the differential equation, let where is the exponent of .
Step 2
Solve the equation for .
Step 3
Take the derivative of with respect to .
Step 4
Take the derivative of with respect to .
Tap for more steps...
Step 4.1
Take the derivative of .
Step 4.2
Rewrite the expression using the negative exponent rule .
Step 4.3
Differentiate using the Quotient Rule which states that is where and .
Step 4.4
Simplify the expression.
Tap for more steps...
Step 4.4.1
Multiply by .
Step 4.4.2
Multiply the exponents in .
Tap for more steps...
Step 4.4.2.1
Apply the power rule and multiply exponents, .
Step 4.4.2.2
Cancel the common factor of .
Tap for more steps...
Step 4.4.2.2.1
Cancel the common factor.
Step 4.4.2.2.2
Rewrite the expression.
Step 4.5
Simplify.
Step 4.6
Differentiate using the Constant Rule.
Tap for more steps...
Step 4.6.1
Since is constant with respect to , the derivative of with respect to is .
Step 4.6.2
Simplify the expression.
Tap for more steps...
Step 4.6.2.1
Multiply by .
Step 4.6.2.2
Subtract from .
Step 4.6.2.3
Move the negative in front of the fraction.
Step 4.7
Differentiate using the chain rule, which states that is where and .
Tap for more steps...
Step 4.7.1
To apply the Chain Rule, set as .
Step 4.7.2
Differentiate using the Power Rule which states that is where .
Step 4.7.3
Replace all occurrences of with .
Step 4.8
To write as a fraction with a common denominator, multiply by .
Step 4.9
Combine and .
Step 4.10
Combine the numerators over the common denominator.
Step 4.11
Simplify the numerator.
Tap for more steps...
Step 4.11.1
Multiply by .
Step 4.11.2
Subtract from .
Step 4.12
Move the negative in front of the fraction.
Step 4.13
Combine and .
Step 4.14
Move to the denominator using the negative exponent rule .
Step 4.15
Rewrite as .
Step 4.16
Combine and .
Step 4.17
Rewrite as a product.
Step 4.18
Multiply by .
Step 4.19
Raise to the power of .
Step 4.20
Use the power rule to combine exponents.
Step 4.21
Write as a fraction with a common denominator.
Step 4.22
Combine the numerators over the common denominator.
Step 4.23
Add and .
Step 5
Substitute for and for in the original equation .
Step 6
Solve the substituted differential equation.
Tap for more steps...
Step 6.1
Separate the variables.
Tap for more steps...
Step 6.1.1
Solve for .
Tap for more steps...
Step 6.1.1.1
Simplify each term.
Tap for more steps...
Step 6.1.1.1.1
Rewrite the expression using the negative exponent rule .
Step 6.1.1.1.2
Multiply the exponents in .
Tap for more steps...
Step 6.1.1.1.2.1
Apply the power rule and multiply exponents, .
Step 6.1.1.1.2.2
Multiply .
Tap for more steps...
Step 6.1.1.1.2.2.1
Multiply by .
Step 6.1.1.1.2.2.2
Combine and .
Step 6.1.1.1.2.3
Move the negative in front of the fraction.
Step 6.1.1.1.3
Rewrite the expression using the negative exponent rule .
Step 6.1.1.2
Move all terms not containing to the right side of the equation.
Tap for more steps...
Step 6.1.1.2.1
Add to both sides of the equation.
Step 6.1.1.2.2
Add to both sides of the equation.
Step 6.1.1.3
Divide each term in by and simplify.
Tap for more steps...
Step 6.1.1.3.1
Divide each term in by .
Step 6.1.1.3.2
Simplify the left side.
Tap for more steps...
Step 6.1.1.3.2.1
Dividing two negative values results in a positive value.
Step 6.1.1.3.2.2
Divide by .
Step 6.1.1.3.3
Simplify the right side.
Tap for more steps...
Step 6.1.1.3.3.1
Simplify each term.
Tap for more steps...
Step 6.1.1.3.3.1.1
Move the negative one from the denominator of .
Step 6.1.1.3.3.1.2
Rewrite as .
Step 6.1.1.3.3.1.3
Move the negative one from the denominator of .
Step 6.1.1.3.3.1.4
Rewrite as .
Step 6.1.1.4
Multiply both sides by .
Step 6.1.1.5
Simplify.
Tap for more steps...
Step 6.1.1.5.1
Simplify the left side.
Tap for more steps...
Step 6.1.1.5.1.1
Simplify .
Tap for more steps...
Step 6.1.1.5.1.1.1
Rewrite using the commutative property of multiplication.
Step 6.1.1.5.1.1.2
Cancel the common factor of .
Tap for more steps...
Step 6.1.1.5.1.1.2.1
Cancel the common factor.
Step 6.1.1.5.1.1.2.2
Rewrite the expression.
Step 6.1.1.5.1.1.3
Cancel the common factor of .
Tap for more steps...
Step 6.1.1.5.1.1.3.1
Cancel the common factor.
Step 6.1.1.5.1.1.3.2
Rewrite the expression.
Step 6.1.1.5.2
Simplify the right side.
Tap for more steps...
Step 6.1.1.5.2.1
Simplify .
Tap for more steps...
Step 6.1.1.5.2.1.1
Simplify terms.
Tap for more steps...
Step 6.1.1.5.2.1.1.1
Apply the distributive property.
Step 6.1.1.5.2.1.1.2
Cancel the common factor of .
Tap for more steps...
Step 6.1.1.5.2.1.1.2.1
Move the leading negative in into the numerator.
Step 6.1.1.5.2.1.1.2.2
Factor out of .
Step 6.1.1.5.2.1.1.2.3
Cancel the common factor.
Step 6.1.1.5.2.1.1.2.4
Rewrite the expression.
Step 6.1.1.5.2.1.1.3
Multiply by .
Step 6.1.1.5.2.1.1.4
Cancel the common factor of .
Tap for more steps...
Step 6.1.1.5.2.1.1.4.1
Move the leading negative in into the numerator.
Step 6.1.1.5.2.1.1.4.2
Factor out of .
Step 6.1.1.5.2.1.1.4.3
Cancel the common factor.
Step 6.1.1.5.2.1.1.4.4
Rewrite the expression.
Step 6.1.1.5.2.1.1.5
Multiply by .
Step 6.1.1.5.2.1.2
Simplify each term.
Tap for more steps...
Step 6.1.1.5.2.1.2.1
Divide by .
Step 6.1.1.5.2.1.2.2
Simplify.
Step 6.1.2
Multiply both sides by .
Step 6.1.3
Simplify.
Tap for more steps...
Step 6.1.3.1
Factor out of .
Tap for more steps...
Step 6.1.3.1.1
Factor out of .
Step 6.1.3.1.2
Factor out of .
Step 6.1.3.1.3
Factor out of .
Step 6.1.3.2
Multiply by .
Step 6.1.3.3
Cancel the common factor of and .
Tap for more steps...
Step 6.1.3.3.1
Factor out of .
Step 6.1.3.3.2
Factor out of .
Step 6.1.3.3.3
Factor out of .
Step 6.1.3.3.4
Cancel the common factors.
Tap for more steps...
Step 6.1.3.3.4.1
Cancel the common factor.
Step 6.1.3.3.4.2
Rewrite the expression.
Step 6.1.3.4
Cancel the common factor of .
Tap for more steps...
Step 6.1.3.4.1
Cancel the common factor.
Step 6.1.3.4.2
Rewrite the expression.
Step 6.1.4
Rewrite the equation.
Step 6.2
Integrate both sides.
Tap for more steps...
Step 6.2.1
Set up an integral on each side.
Step 6.2.2
Integrate the left side.
Tap for more steps...
Step 6.2.2.1
Let . Then , so . Rewrite using and .
Tap for more steps...
Step 6.2.2.1.1
Let . Find .
Tap for more steps...
Step 6.2.2.1.1.1
Differentiate .
Step 6.2.2.1.1.2
By the Sum Rule, the derivative of with respect to is .
Step 6.2.2.1.1.3
Evaluate .
Tap for more steps...
Step 6.2.2.1.1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 6.2.2.1.1.3.2
Differentiate using the Power Rule which states that is where .
Step 6.2.2.1.1.3.3
Multiply by .
Step 6.2.2.1.1.4
Differentiate using the Constant Rule.
Tap for more steps...
Step 6.2.2.1.1.4.1
Since is constant with respect to , the derivative of with respect to is .
Step 6.2.2.1.1.4.2
Add and .
Step 6.2.2.1.2
Rewrite the problem using and .
Step 6.2.2.2
Simplify.
Tap for more steps...
Step 6.2.2.2.1
Move the negative in front of the fraction.
Step 6.2.2.2.2
Multiply by .
Step 6.2.2.2.3
Move to the left of .
Step 6.2.2.3
Since is constant with respect to , move out of the integral.
Step 6.2.2.4
Since is constant with respect to , move out of the integral.
Step 6.2.2.5
The integral of with respect to is .
Step 6.2.2.6
Simplify.
Step 6.2.2.7
Replace all occurrences of with .
Step 6.2.3
Apply the constant rule.
Step 6.2.4
Group the constant of integration on the right side as .
Step 6.3
Solve for .
Tap for more steps...
Step 6.3.1
Multiply both sides of the equation by .
Step 6.3.2
Simplify both sides of the equation.
Tap for more steps...
Step 6.3.2.1
Simplify the left side.
Tap for more steps...
Step 6.3.2.1.1
Simplify .
Tap for more steps...
Step 6.3.2.1.1.1
Combine and .
Step 6.3.2.1.1.2
Cancel the common factor of .
Tap for more steps...
Step 6.3.2.1.1.2.1
Move the leading negative in into the numerator.
Step 6.3.2.1.1.2.2
Factor out of .
Step 6.3.2.1.1.2.3
Cancel the common factor.
Step 6.3.2.1.1.2.4
Rewrite the expression.
Step 6.3.2.1.1.3
Multiply.
Tap for more steps...
Step 6.3.2.1.1.3.1
Multiply by .
Step 6.3.2.1.1.3.2
Multiply by .
Step 6.3.2.2
Simplify the right side.
Tap for more steps...
Step 6.3.2.2.1
Apply the distributive property.
Step 6.3.3
To solve for , rewrite the equation using properties of logarithms.
Step 6.3.4
Rewrite in exponential form using the definition of a logarithm. If and are positive real numbers and , then is equivalent to .
Step 6.3.5
Solve for .
Tap for more steps...
Step 6.3.5.1
Rewrite the equation as .
Step 6.3.5.2
Remove the absolute value term. This creates a on the right side of the equation because .
Step 6.3.5.3
Add to both sides of the equation.
Step 6.3.5.4
Divide each term in by and simplify.
Tap for more steps...
Step 6.3.5.4.1
Divide each term in by .
Step 6.3.5.4.2
Simplify the left side.
Tap for more steps...
Step 6.3.5.4.2.1
Cancel the common factor of .
Tap for more steps...
Step 6.3.5.4.2.1.1
Cancel the common factor.
Step 6.3.5.4.2.1.2
Divide by .
Step 6.3.5.4.3
Simplify the right side.
Tap for more steps...
Step 6.3.5.4.3.1
Simplify each term.
Tap for more steps...
Step 6.3.5.4.3.1.1
Simplify .
Step 6.3.5.4.3.1.2
Divide by .
Step 6.3.5.4.3.2
To write as a fraction with a common denominator, multiply by .
Step 6.3.5.4.3.3
Combine and .
Step 6.3.5.4.3.4
Combine the numerators over the common denominator.
Step 6.3.5.4.3.5
Multiply by .
Step 6.4
Group the constant terms together.
Tap for more steps...
Step 6.4.1
Simplify the constant of integration.
Step 6.4.2
Rewrite as .
Step 6.4.3
Reorder and .
Step 6.4.4
Combine constants with the plus or minus.
Step 7
Substitute for .