Calculus Examples
dydx-y=exy2dydx−y=exy2
Step 1
To solve the differential equation, let v=y1-nv=y1−n where nn is the exponent of y2y2.
v=y-1v=y−1
Step 2
Solve the equation for yy.
y=v-1y=v−1
Step 3
Take the derivative of yy with respect to xx.
y′=v-1
Step 4
Step 4.1
Take the derivative of v-1.
y′=ddx[v-1]
Step 4.2
Rewrite the expression using the negative exponent rule b-n=1bn.
y′=ddx[1v]
Step 4.3
Differentiate using the Quotient Rule which states that ddx[f(x)g(x)] is g(x)ddx[f(x)]-f(x)ddx[g(x)]g(x)2 where f(x)=1 and g(x)=v.
y′=vddx[1]-1⋅1ddx[v]v2
Step 4.4
Differentiate using the Constant Rule.
Step 4.4.1
Multiply -1 by 1.
y′=vddx[1]-ddx[v]v2
Step 4.4.2
Since 1 is constant with respect to x, the derivative of 1 with respect to x is 0.
y′=v⋅0-ddx[v]v2
Step 4.4.3
Simplify the expression.
Step 4.4.3.1
Multiply v by 0.
y′=0-ddx[v]v2
Step 4.4.3.2
Subtract ddx[v] from 0.
y′=-ddx[v]v2
Step 4.4.3.3
Move the negative in front of the fraction.
y′=-ddx[v]v2
y′=-ddx[v]v2
y′=-ddx[v]v2
Step 4.5
Rewrite ddx[v] as v′.
y′=-v′v2
y′=-v′v2
Step 5
Substitute -v′v2 for dydx and v-1 for y in the original equation dydx-y=exy2.
-v′v2-v-1=ex(v-1)2
Step 6
Step 6.1
Multiply each term in -dvdxv2-v-1=ex(v-1)2 by -v2 to eliminate the fractions.
Step 6.1.1
Multiply each term in -dvdxv2-v-1=ex(v-1)2 by -v2.
-dvdxv2(-v2)-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2
Simplify the left side.
Step 6.1.2.1
Simplify each term.
Step 6.1.2.1.1
Cancel the common factor of v2.
Step 6.1.2.1.1.1
Move the leading negative in -dvdxv2 into the numerator.
-dvdxv2(-v2)-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2.1.1.2
Factor v2 out of -v2.
-dvdxv2(v2⋅-1)-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2.1.1.3
Cancel the common factor.
-dvdxv2(v2⋅-1)-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2.1.1.4
Rewrite the expression.
-dvdx⋅-1-v-1(-v2)=ex(v-1)2(-v2)
-dvdx⋅-1-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2.1.2
Multiply -1 by -1.
1dvdx-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2.1.3
Multiply dvdx by 1.
dvdx-v-1(-v2)=ex(v-1)2(-v2)
Step 6.1.2.1.4
Rewrite using the commutative property of multiplication.
dvdx-1⋅-1v-1v2=ex(v-1)2(-v2)
Step 6.1.2.1.5
Multiply v-1 by v2 by adding the exponents.
Step 6.1.2.1.5.1
Move v2.
dvdx-1⋅-1(v2v-1)=ex(v-1)2(-v2)
Step 6.1.2.1.5.2
Use the power rule aman=am+n to combine exponents.
dvdx-1⋅-1v2-1=ex(v-1)2(-v2)
Step 6.1.2.1.5.3
Subtract 1 from 2.
dvdx-1⋅-1v1=ex(v-1)2(-v2)
dvdx-1⋅-1v1=ex(v-1)2(-v2)
Step 6.1.2.1.6
Simplify -1⋅-1v1.
dvdx-1⋅-1v=ex(v-1)2(-v2)
Step 6.1.2.1.7
Multiply -1 by -1.
dvdx+1v=ex(v-1)2(-v2)
Step 6.1.2.1.8
Multiply v by 1.
dvdx+v=ex(v-1)2(-v2)
dvdx+v=ex(v-1)2(-v2)
dvdx+v=ex(v-1)2(-v2)
Step 6.1.3
Simplify the right side.
Step 6.1.3.1
Rewrite using the commutative property of multiplication.
dvdx+v=-ex(v-1)2v2
Step 6.1.3.2
Multiply the exponents in (v-1)2.
Step 6.1.3.2.1
Apply the power rule and multiply exponents, (am)n=amn.
dvdx+v=-exv-1⋅2v2
Step 6.1.3.2.2
Multiply -1 by 2.
dvdx+v=-exv-2v2
dvdx+v=-exv-2v2
Step 6.1.3.3
Multiply v-2 by v2 by adding the exponents.
Step 6.1.3.3.1
Move v2.
dvdx+v=-ex(v2v-2)
Step 6.1.3.3.2
Use the power rule aman=am+n to combine exponents.
dvdx+v=-exv2-2
Step 6.1.3.3.3
Subtract 2 from 2.
dvdx+v=-exv0
dvdx+v=-exv0
Step 6.1.3.4
Simplify -exv0.
dvdx+v=-ex
dvdx+v=-ex
dvdx+v=-ex
Step 6.2
The integrating factor is defined by the formula e∫P(x)dx, where P(x)=1.
Step 6.2.1
Set up the integration.
e∫dx
Step 6.2.2
Apply the constant rule.
ex+C
Step 6.2.3
Remove the constant of integration.
ex
ex
Step 6.3
Multiply each term by the integrating factor ex.
Step 6.3.1
Multiply each term by ex.
exdvdx+exv=ex(-ex)
Step 6.3.2
Rewrite using the commutative property of multiplication.
exdvdx+exv=-exex
Step 6.3.3
Multiply ex by ex by adding the exponents.
Step 6.3.3.1
Move ex.
exdvdx+exv=-(exex)
Step 6.3.3.2
Use the power rule aman=am+n to combine exponents.
exdvdx+exv=-ex+x
Step 6.3.3.3
Add x and x.
exdvdx+exv=-e2x
exdvdx+exv=-e2x
Step 6.3.4
Reorder factors in exdvdx+exv=-e2x.
exdvdx+vex=-e2x
exdvdx+vex=-e2x
Step 6.4
Rewrite the left side as a result of differentiating a product.
ddx[exv]=-e2x
Step 6.5
Set up an integral on each side.
∫ddx[exv]dx=∫-e2xdx
Step 6.6
Integrate the left side.
exv=∫-e2xdx
Step 6.7
Integrate the right side.
Step 6.7.1
Since -1 is constant with respect to x, move -1 out of the integral.
exv=-∫e2xdx
Step 6.7.2
Let u=2x. Then du=2dx, so 12du=dx. Rewrite using u and du.
Step 6.7.2.1
Let u=2x. Find dudx.
Step 6.7.2.1.1
Differentiate 2x.
ddx[2x]
Step 6.7.2.1.2
Since 2 is constant with respect to x, the derivative of 2x with respect to x is 2ddx[x].
2ddx[x]
Step 6.7.2.1.3
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=1.
2⋅1
Step 6.7.2.1.4
Multiply 2 by 1.
2
2
Step 6.7.2.2
Rewrite the problem using u and du.
exv=-∫eu12du
exv=-∫eu12du
Step 6.7.3
Combine eu and 12.
exv=-∫eu2du
Step 6.7.4
Since 12 is constant with respect to u, move 12 out of the integral.
exv=-(12∫eudu)
Step 6.7.5
The integral of eu with respect to u is eu.
exv=-12(eu+C)
Step 6.7.6
Simplify.
exv=-12eu+C
Step 6.7.7
Replace all occurrences of u with 2x.
exv=-12e2x+C
exv=-12e2x+C
Step 6.8
Divide each term in exv=-12e2x+C by ex and simplify.
Step 6.8.1
Divide each term in exv=-12e2x+C by ex.
exvex=-12e2xex+Cex
Step 6.8.2
Simplify the left side.
Step 6.8.2.1
Cancel the common factor of ex.
Step 6.8.2.1.1
Cancel the common factor.
exvex=-12e2xex+Cex
Step 6.8.2.1.2
Divide v by 1.
v=-12e2xex+Cex
v=-12e2xex+Cex
v=-12e2xex+Cex
Step 6.8.3
Simplify the right side.
Step 6.8.3.1
Simplify each term.
Step 6.8.3.1.1
Cancel the common factor of e2x and ex.
Step 6.8.3.1.1.1
Factor ex out of -12e2x.
v=ex(-12ex)ex+Cex
Step 6.8.3.1.1.2
Cancel the common factors.
Step 6.8.3.1.1.2.1
Multiply by 1.
v=ex(-12ex)ex⋅1+Cex
Step 6.8.3.1.1.2.2
Cancel the common factor.
v=ex(-12ex)ex⋅1+Cex
Step 6.8.3.1.1.2.3
Rewrite the expression.
v=-12ex1+Cex
Step 6.8.3.1.1.2.4
Divide -12ex by 1.
v=-12ex+Cex
v=-12ex+Cex
v=-12ex+Cex
Step 6.8.3.1.2
Combine ex and 12.
v=-ex2+Cex
v=-ex2+Cex
v=-ex2+Cex
v=-ex2+Cex
v=-ex2+Cex
Step 7
Substitute y-1 for v.
y-1=-ex2+Cex