How do i solve differential equations?

To solve differential equations we use a method called separation of variables. This is where we take all the ‘y’ values to one side of the equation and all the ‘x’ values to the other side of the equation make sure the ‘y’ terms are on the same side as the ‘dy/dx’. We then integrate both sides of the equation with respect to the variable of that side. We then if possible rearrange to equation with respect to y.

 

For example:

Solve this differential equation.

 

dy/dx = (3x2)/(y+1)

 

Step 1: Rearrange the equation so that the ‘y’ terms are on one side of the                                    equation and the ‘x’ terms are on the other side of the equation.

 

Times both sides by: (y+1).

 

(y+1)dy/dx = 3x2

 

Step 2: Integrate both sides with respect to x.

 

∫ (y+1) dx dy/dx = ∫ 3x2 dx

 

(The ‘dx’s cancel on the left side of the equation leaving ‘dy’, this means we integrate the left side with respect to ‘y’ now).

 

 

∫ (y+1) dy = ∫ 3x2 dx

 

(y2/2) + y = x+ c

 

(You only need one constant in the solution for differential equations.)

 

It is not possible to rearrange this equation with respect to y so we leave it as it is.

 

 

SS
Answered by Stephen S. Maths tutor

6740 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

how to write down the differential equation from a word problem, involving rate of change.


How do I find the area bounded by the curve y=-x^2+4 and the line y=-x+2?


The gradient of a curve is defined as Dy/dx = 3x^2 + 3x and it passes through the point (0,0), what is the equation of the curve


Differentiate sin3x-3x= f(x)


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning