Calculus Examples

Solve the Differential Equation (dx)/(dt)=(x-1)(1-2x)
Step 1
Separate the variables.
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Step 1.1
Multiply both sides by .
Step 1.2
Cancel the common factor of .
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Step 1.2.1
Cancel the common factor.
Step 1.2.2
Rewrite the expression.
Step 1.3
Rewrite the equation.
Step 2
Integrate both sides.
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Step 2.1
Set up an integral on each side.
Step 2.2
Integrate the left side.
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Step 2.2.1
Write the fraction using partial fraction decomposition.
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Step 2.2.1.1
Decompose the fraction and multiply through by the common denominator.
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Step 2.2.1.1.1
For each factor in the denominator, create a new fraction using the factor as the denominator, and an unknown value as the numerator. Since the factor in the denominator is linear, put a single variable in its place .
Step 2.2.1.1.2
For each factor in the denominator, create a new fraction using the factor as the denominator, and an unknown value as the numerator. Since the factor in the denominator is linear, put a single variable in its place .
Step 2.2.1.1.3
Multiply each fraction in the equation by the denominator of the original expression. In this case, the denominator is .
Step 2.2.1.1.4
Cancel the common factor of .
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Step 2.2.1.1.4.1
Cancel the common factor.
Step 2.2.1.1.4.2
Rewrite the expression.
Step 2.2.1.1.5
Cancel the common factor of .
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Step 2.2.1.1.5.1
Cancel the common factor.
Step 2.2.1.1.5.2
Rewrite the expression.
Step 2.2.1.1.6
Simplify each term.
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Step 2.2.1.1.6.1
Cancel the common factor of .
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Step 2.2.1.1.6.1.1
Cancel the common factor.
Step 2.2.1.1.6.1.2
Divide by .
Step 2.2.1.1.6.2
Apply the distributive property.
Step 2.2.1.1.6.3
Multiply by .
Step 2.2.1.1.6.4
Rewrite using the commutative property of multiplication.
Step 2.2.1.1.6.5
Cancel the common factor of .
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Step 2.2.1.1.6.5.1
Cancel the common factor.
Step 2.2.1.1.6.5.2
Divide by .
Step 2.2.1.1.6.6
Apply the distributive property.
Step 2.2.1.1.6.7
Move to the left of .
Step 2.2.1.1.6.8
Rewrite as .
Step 2.2.1.1.7
Simplify the expression.
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Step 2.2.1.1.7.1
Move .
Step 2.2.1.1.7.2
Reorder and .
Step 2.2.1.1.7.3
Move .
Step 2.2.1.2
Create equations for the partial fraction variables and use them to set up a system of equations.
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Step 2.2.1.2.1
Create an equation for the partial fraction variables by equating the coefficients of from each side of the equation. For the equation to be equal, the equivalent coefficients on each side of the equation must be equal.
Step 2.2.1.2.2
Create an equation for the partial fraction variables by equating the coefficients of the terms not containing . For the equation to be equal, the equivalent coefficients on each side of the equation must be equal.
Step 2.2.1.2.3
Set up the system of equations to find the coefficients of the partial fractions.
Step 2.2.1.3
Solve the system of equations.
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Step 2.2.1.3.1
Solve for in .
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Step 2.2.1.3.1.1
Rewrite the equation as .
Step 2.2.1.3.1.2
Add to both sides of the equation.
Step 2.2.1.3.2
Replace all occurrences of with in each equation.
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Step 2.2.1.3.2.1
Replace all occurrences of in with .
Step 2.2.1.3.2.2
Simplify the right side.
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Step 2.2.1.3.2.2.1
Simplify .
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Step 2.2.1.3.2.2.1.1
Multiply by .
Step 2.2.1.3.2.2.1.2
Subtract from .
Step 2.2.1.3.3
Solve for in .
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Step 2.2.1.3.3.1
Rewrite the equation as .
Step 2.2.1.3.3.2
Divide each term in by and simplify.
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Step 2.2.1.3.3.2.1
Divide each term in by .
Step 2.2.1.3.3.2.2
Simplify the left side.
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Step 2.2.1.3.3.2.2.1
Dividing two negative values results in a positive value.
Step 2.2.1.3.3.2.2.2
Divide by .
Step 2.2.1.3.3.2.3
Simplify the right side.
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Step 2.2.1.3.3.2.3.1
Divide by .
Step 2.2.1.3.4
Replace all occurrences of with in each equation.
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Step 2.2.1.3.4.1
Replace all occurrences of in with .
Step 2.2.1.3.4.2
Simplify the right side.
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Step 2.2.1.3.4.2.1
Multiply by .
Step 2.2.1.3.5
List all of the solutions.
Step 2.2.1.4
Replace each of the partial fraction coefficients in with the values found for and .
Step 2.2.1.5
Simplify.
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Step 2.2.1.5.1
Move the negative in front of the fraction.
Step 2.2.1.5.2
Move the negative in front of the fraction.
Step 2.2.2
Split the single integral into multiple integrals.
Step 2.2.3
Since is constant with respect to , move out of the integral.
Step 2.2.4
Let . Then . Rewrite using and .
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Step 2.2.4.1
Let . Find .
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Step 2.2.4.1.1
Differentiate .
Step 2.2.4.1.2
By the Sum Rule, the derivative of with respect to is .
Step 2.2.4.1.3
Differentiate using the Power Rule which states that is where .
Step 2.2.4.1.4
Since is constant with respect to , the derivative of with respect to is .
Step 2.2.4.1.5
Add and .
Step 2.2.4.2
Rewrite the problem using and .
Step 2.2.5
The integral of with respect to is .
Step 2.2.6
Since is constant with respect to , move out of the integral.
Step 2.2.7
Since is constant with respect to , move out of the integral.
Step 2.2.8
Multiply by .
Step 2.2.9
Let . Then , so . Rewrite using and .
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Step 2.2.9.1
Let . Find .
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Step 2.2.9.1.1
Differentiate .
Step 2.2.9.1.2
Differentiate.
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Step 2.2.9.1.2.1
By the Sum Rule, the derivative of with respect to is .
Step 2.2.9.1.2.2
Since is constant with respect to , the derivative of with respect to is .
Step 2.2.9.1.3
Evaluate .
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Step 2.2.9.1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.2.9.1.3.2
Differentiate using the Power Rule which states that is where .
Step 2.2.9.1.3.3
Multiply by .
Step 2.2.9.1.4
Subtract from .
Step 2.2.9.2
Rewrite the problem using and .
Step 2.2.10
Simplify.
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Step 2.2.10.1
Move the negative in front of the fraction.
Step 2.2.10.2
Multiply by .
Step 2.2.10.3
Move to the left of .
Step 2.2.11
Since is constant with respect to , move out of the integral.
Step 2.2.12
Multiply by .
Step 2.2.13
Since is constant with respect to , move out of the integral.
Step 2.2.14
Simplify.
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Step 2.2.14.1
Combine and .
Step 2.2.14.2
Cancel the common factor of .
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Step 2.2.14.2.1
Cancel the common factor.
Step 2.2.14.2.2
Rewrite the expression.
Step 2.2.14.3
Multiply by .
Step 2.2.15
The integral of with respect to is .
Step 2.2.16
Simplify.
Step 2.2.17
Substitute back in for each integration substitution variable.
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Step 2.2.17.1
Replace all occurrences of with .
Step 2.2.17.2
Replace all occurrences of with .
Step 2.2.18
Reorder terms.
Step 2.3
Apply the constant rule.
Step 2.4
Group the constant of integration on the right side as .
Step 3
Solve for .
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Step 3.1
Use the quotient property of logarithms, .
Step 3.2
Reorder and .
Step 3.3
To solve for , rewrite the equation using properties of logarithms.
Step 3.4
Rewrite in exponential form using the definition of a logarithm. If and are positive real numbers and , then is equivalent to .
Step 3.5
Solve for .
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Step 3.5.1
Rewrite the equation as .
Step 3.5.2
Multiply both sides by .
Step 3.5.3
Simplify the left side.
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Step 3.5.3.1
Cancel the common factor of .
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Step 3.5.3.1.1
Cancel the common factor.
Step 3.5.3.1.2
Rewrite the expression.
Step 3.5.4
Solve for .
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Step 3.5.4.1
Rewrite the equation as .
Step 3.5.4.2
Divide each term in by and simplify.
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Step 3.5.4.2.1
Divide each term in by .
Step 3.5.4.2.2
Simplify the left side.
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Step 3.5.4.2.2.1
Cancel the common factor of .
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Step 3.5.4.2.2.1.1
Cancel the common factor.
Step 3.5.4.2.2.1.2
Divide by .
Step 3.5.4.3
Rewrite the absolute value equation as four equations without absolute value bars.
Step 3.5.4.4
After simplifying, there are only two unique equations to be solved.
Step 3.5.4.5
Solve for .
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Step 3.5.4.5.1
Multiply both sides by .
Step 3.5.4.5.2
Simplify.
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Step 3.5.4.5.2.1
Simplify the left side.
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Step 3.5.4.5.2.1.1
Simplify .
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Step 3.5.4.5.2.1.1.1
Apply the distributive property.
Step 3.5.4.5.2.1.1.2
Rewrite as .
Step 3.5.4.5.2.2
Simplify the right side.
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Step 3.5.4.5.2.2.1
Simplify .
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Step 3.5.4.5.2.2.1.1
Cancel the common factor of .
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Step 3.5.4.5.2.2.1.1.1
Cancel the common factor.
Step 3.5.4.5.2.2.1.1.2
Rewrite the expression.
Step 3.5.4.5.2.2.1.2
Reorder and .
Step 3.5.4.5.3
Solve for .
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Step 3.5.4.5.3.1
Add to both sides of the equation.
Step 3.5.4.5.3.2
Add to both sides of the equation.
Step 3.5.4.5.3.3
Factor out of .
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Step 3.5.4.5.3.3.1
Factor out of .
Step 3.5.4.5.3.3.2
Factor out of .
Step 3.5.4.5.3.3.3
Factor out of .
Step 3.5.4.5.3.4
Divide each term in by and simplify.
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Step 3.5.4.5.3.4.1
Divide each term in by .
Step 3.5.4.5.3.4.2
Simplify the left side.
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Step 3.5.4.5.3.4.2.1
Cancel the common factor of .
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Step 3.5.4.5.3.4.2.1.1
Cancel the common factor.
Step 3.5.4.5.3.4.2.1.2
Divide by .
Step 3.5.4.5.3.4.3
Simplify the right side.
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Step 3.5.4.5.3.4.3.1
Combine the numerators over the common denominator.
Step 3.5.4.6
Solve for .
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Step 3.5.4.6.1
Multiply both sides by .
Step 3.5.4.6.2
Simplify.
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Step 3.5.4.6.2.1
Simplify the left side.
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Step 3.5.4.6.2.1.1
Simplify .
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Step 3.5.4.6.2.1.1.1
Apply the distributive property.
Step 3.5.4.6.2.1.1.2
Rewrite as .
Step 3.5.4.6.2.2
Simplify the right side.
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Step 3.5.4.6.2.2.1
Simplify .
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Step 3.5.4.6.2.2.1.1
Cancel the common factor of .
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Step 3.5.4.6.2.2.1.1.1
Move the leading negative in into the numerator.
Step 3.5.4.6.2.2.1.1.2
Cancel the common factor.
Step 3.5.4.6.2.2.1.1.3
Rewrite the expression.
Step 3.5.4.6.2.2.1.2
Apply the distributive property.
Step 3.5.4.6.2.2.1.3
Simplify the expression.
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Step 3.5.4.6.2.2.1.3.1
Multiply by .
Step 3.5.4.6.2.2.1.3.2
Multiply by .
Step 3.5.4.6.2.2.1.3.3
Reorder and .
Step 3.5.4.6.3
Solve for .
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Step 3.5.4.6.3.1
Subtract from both sides of the equation.
Step 3.5.4.6.3.2
Add to both sides of the equation.
Step 3.5.4.6.3.3
Factor out of .
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Step 3.5.4.6.3.3.1
Factor out of .
Step 3.5.4.6.3.3.2
Factor out of .
Step 3.5.4.6.3.3.3
Factor out of .
Step 3.5.4.6.3.4
Divide each term in by and simplify.
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Step 3.5.4.6.3.4.1
Divide each term in by .
Step 3.5.4.6.3.4.2
Simplify the left side.
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Step 3.5.4.6.3.4.2.1
Cancel the common factor of .
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Step 3.5.4.6.3.4.2.1.1
Cancel the common factor.
Step 3.5.4.6.3.4.2.1.2
Divide by .
Step 3.5.4.6.3.4.3
Simplify the right side.
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Step 3.5.4.6.3.4.3.1
Combine the numerators over the common denominator.
Step 3.5.4.6.3.4.3.2
Rewrite as .
Step 3.5.4.6.3.4.3.3
Factor out of .
Step 3.5.4.6.3.4.3.4
Factor out of .
Step 3.5.4.6.3.4.3.5
Move the negative in front of the fraction.
Step 3.5.4.7
List all of the solutions.
Step 4
Group the constant terms together.
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Step 4.1
Reorder terms.
Step 4.2
Rewrite as .
Step 4.3
Reorder and .
Step 4.4
Reorder terms.
Step 4.5
Rewrite as .
Step 4.6
Reorder and .
Step 4.7
Reorder terms.
Step 4.8
Rewrite as .
Step 4.9
Reorder and .
Step 4.10
Reorder terms.
Step 4.11
Rewrite as .
Step 4.12
Reorder and .