Calculus Examples

Solve the Differential Equation (dy)/(dx)=(7e^x-3e^(-x))^2
dydx=(7ex-3e-x)2
Step 1
Rewrite the equation.
dy=(7ex-3e-x)2dx
Step 2
Integrate both sides.
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Step 2.1
Set up an integral on each side.
dy=(7ex-3e-x)2dx
Step 2.2
Apply the constant rule.
y+C1=(7ex-3e-x)2dx
Step 2.3
Integrate the right side.
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Step 2.3.1
Simplify.
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Step 2.3.1.1
Rewrite (7ex-3e-x)2 as (7ex-3e-x)(7ex-3e-x).
y+C1=(7ex-3e-x)(7ex-3e-x)dx
Step 2.3.1.2
Expand (7ex-3e-x)(7ex-3e-x) using the FOIL Method.
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Step 2.3.1.2.1
Apply the distributive property.
y+C1=7ex(7ex-3e-x)-3e-x(7ex-3e-x)dx
Step 2.3.1.2.2
Apply the distributive property.
y+C1=7ex(7ex)+7ex(-3e-x)-3e-x(7ex-3e-x)dx
Step 2.3.1.2.3
Apply the distributive property.
y+C1=7ex(7ex)+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
y+C1=7ex(7ex)+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3
Simplify and combine like terms.
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Step 2.3.1.3.1
Simplify each term.
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Step 2.3.1.3.1.1
Rewrite using the commutative property of multiplication.
y+C1=77exex+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.2
Multiply ex by ex by adding the exponents.
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Step 2.3.1.3.1.2.1
Move ex.
y+C1=77(exex)+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.2.2
Use the power rule aman=am+n to combine exponents.
y+C1=77ex+x+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.2.3
Add x and x.
y+C1=77e2x+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
y+C1=77e2x+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.3
Multiply 7 by 7.
y+C1=49e2x+7ex(-3e-x)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.4
Rewrite using the commutative property of multiplication.
y+C1=49e2x+7-3exe-x-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.5
Multiply ex by e-x by adding the exponents.
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Step 2.3.1.3.1.5.1
Move e-x.
y+C1=49e2x+7-3(e-xex)-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.5.2
Use the power rule aman=am+n to combine exponents.
y+C1=49e2x+7-3e-x+x-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.5.3
Add -x and x.
y+C1=49e2x+7-3e0-3e-x(7ex)-3e-x(-3e-x)dx
y+C1=49e2x+7-3e0-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.6
Simplify 7-3e0.
y+C1=49e2x+7-3-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.7
Multiply 7 by -3.
y+C1=49e2x-21-3e-x(7ex)-3e-x(-3e-x)dx
Step 2.3.1.3.1.8
Rewrite using the commutative property of multiplication.
y+C1=49e2x-21-37e-xex-3e-x(-3e-x)dx
Step 2.3.1.3.1.9
Multiply e-x by ex by adding the exponents.
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Step 2.3.1.3.1.9.1
Move ex.
y+C1=49e2x-21-37(exe-x)-3e-x(-3e-x)dx
Step 2.3.1.3.1.9.2
Use the power rule aman=am+n to combine exponents.
y+C1=49e2x-21-37ex-x-3e-x(-3e-x)dx
Step 2.3.1.3.1.9.3
Subtract x from x.
y+C1=49e2x-21-37e0-3e-x(-3e-x)dx
y+C1=49e2x-21-37e0-3e-x(-3e-x)dx
Step 2.3.1.3.1.10
Simplify -37e0.
y+C1=49e2x-21-37-3e-x(-3e-x)dx
Step 2.3.1.3.1.11
Multiply -3 by 7.
y+C1=49e2x-21-21-3e-x(-3e-x)dx
Step 2.3.1.3.1.12
Rewrite using the commutative property of multiplication.
y+C1=49e2x-21-21-3-3e-xe-xdx
Step 2.3.1.3.1.13
Multiply e-x by e-x by adding the exponents.
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Step 2.3.1.3.1.13.1
Move e-x.
y+C1=49e2x-21-21-3-3(e-xe-x)dx
Step 2.3.1.3.1.13.2
Use the power rule aman=am+n to combine exponents.
y+C1=49e2x-21-21-3-3e-x-xdx
Step 2.3.1.3.1.13.3
Subtract x from -x.
y+C1=49e2x-21-21-3-3e-2xdx
y+C1=49e2x-21-21-3-3e-2xdx
Step 2.3.1.3.1.14
Multiply -3 by -3.
y+C1=49e2x-21-21+9e-2xdx
y+C1=49e2x-21-21+9e-2xdx
Step 2.3.1.3.2
Subtract 21 from -21.
y+C1=49e2x-42+9e-2xdx
y+C1=49e2x-42+9e-2xdx
y+C1=49e2x-42+9e-2xdx
Step 2.3.2
Split the single integral into multiple integrals.
y+C1=49e2xdx+-42dx+9e-2xdx
Step 2.3.3
Since 49 is constant with respect to x, move 49 out of the integral.
y+C1=49e2xdx+-42dx+9e-2xdx
Step 2.3.4
Let u1=2x. Then du1=2dx, so 12du1=dx. Rewrite using u1 and du1.
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Step 2.3.4.1
Let u1=2x. Find du1dx.
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Step 2.3.4.1.1
Differentiate 2x.
ddx[2x]
Step 2.3.4.1.2
Since 2 is constant with respect to x, the derivative of 2x with respect to x is 2ddx[x].
2ddx[x]
Step 2.3.4.1.3
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=1.
21
Step 2.3.4.1.4
Multiply 2 by 1.
2
2
Step 2.3.4.2
Rewrite the problem using u1 and du1.
y+C1=49eu112du1+-42dx+9e-2xdx
y+C1=49eu112du1+-42dx+9e-2xdx
Step 2.3.5
Combine eu1 and 12.
y+C1=49eu12du1+-42dx+9e-2xdx
Step 2.3.6
Since 12 is constant with respect to u1, move 12 out of the integral.
y+C1=49(12eu1du1)+-42dx+9e-2xdx
Step 2.3.7
Combine 12 and 49.
y+C1=492eu1du1+-42dx+9e-2xdx
Step 2.3.8
The integral of eu1 with respect to u1 is eu1.
y+C1=492(eu1+C2)+-42dx+9e-2xdx
Step 2.3.9
Apply the constant rule.
y+C1=492(eu1+C2)-42x+C3+9e-2xdx
Step 2.3.10
Since 9 is constant with respect to x, move 9 out of the integral.
y+C1=492(eu1+C2)-42x+C3+9e-2xdx
Step 2.3.11
Let u2=-2x. Then du2=-2dx, so -12du2=dx. Rewrite using u2 and du2.
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Step 2.3.11.1
Let u2=-2x. Find du2dx.
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Step 2.3.11.1.1
Differentiate -2x.
ddx[-2x]
Step 2.3.11.1.2
Since -2 is constant with respect to x, the derivative of -2x with respect to x is -2ddx[x].
-2ddx[x]
Step 2.3.11.1.3
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=1.
-21
Step 2.3.11.1.4
Multiply -2 by 1.
-2
-2
Step 2.3.11.2
Rewrite the problem using u2 and du2.
y+C1=492(eu1+C2)-42x+C3+9eu21-2du2
y+C1=492(eu1+C2)-42x+C3+9eu21-2du2
Step 2.3.12
Simplify.
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Step 2.3.12.1
Move the negative in front of the fraction.
y+C1=492(eu1+C2)-42x+C3+9eu2(-12)du2
Step 2.3.12.2
Combine eu2 and 12.
y+C1=492(eu1+C2)-42x+C3+9-eu22du2
y+C1=492(eu1+C2)-42x+C3+9-eu22du2
Step 2.3.13
Since -1 is constant with respect to u2, move -1 out of the integral.
y+C1=492(eu1+C2)-42x+C3+9(-eu22du2)
Step 2.3.14
Multiply -1 by 9.
y+C1=492(eu1+C2)-42x+C3-9eu22du2
Step 2.3.15
Since 12 is constant with respect to u2, move 12 out of the integral.
y+C1=492(eu1+C2)-42x+C3-9(12eu2du2)
Step 2.3.16
Simplify.
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Step 2.3.16.1
Combine 12 and -9.
y+C1=492(eu1+C2)-42x+C3+-92eu2du2
Step 2.3.16.2
Move the negative in front of the fraction.
y+C1=492(eu1+C2)-42x+C3-92eu2du2
y+C1=492(eu1+C2)-42x+C3-92eu2du2
Step 2.3.17
The integral of eu2 with respect to u2 is eu2.
y+C1=492(eu1+C2)-42x+C3-92(eu2+C4)
Step 2.3.18
Simplify.
y+C1=492eu1-42x-92eu2+C5
Step 2.3.19
Substitute back in for each integration substitution variable.
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Step 2.3.19.1
Replace all occurrences of u1 with 2x.
y+C1=492e2x-42x-92eu2+C5
Step 2.3.19.2
Replace all occurrences of u2 with -2x.
y+C1=492e2x-42x-92e-2x+C5
y+C1=492e2x-42x-92e-2x+C5
Step 2.3.20
Reorder terms.
y+C1=492e2x-92e-2x-42x+C5
y+C1=492e2x-92e-2x-42x+C5
Step 2.4
Group the constant of integration on the right side as K.
y=492e2x-92e-2x-42x+K
y=492e2x-92e-2x-42x+K
 [x2  12  π  xdx ]