Friday

November 28, 2014

November 28, 2014

Posted by **Kenneth** on Monday, December 1, 2008 at 9:10pm.

how do i go about solving this??? also, is there a trick to understanding differential equations? i'm really struggling with this idea, but i'm too embarassed to ask my professor for help.

- calculus -
**Damon**, Monday, December 1, 2008 at 9:18pmTo find out if your answer is correct, differentiate it and see if you get the original back.

y = x^3

dy/dx = 3 x^2

now put that in d dy/dx - 3 y

x(3 x^2)- 3 x^3 = ?

3 x^3 - 3 x^3 = 0

sure enough it works

- calculus -
**Damon**, Monday, December 1, 2008 at 9:25pmWell, here try getting all the y stuff on one side and all the x stuff on the other side (separating variables)

x dy/dx = 3 y

dy/y = 3 dx/x

integrate both sides

ln y = 3 ln x

but 3 ln x = ln x^3

so

ln y = ln x^3

so

y = x^3 will work.

**Answer this Question**

**Related Questions**

calculus-differential equation - Consider the differential equation: (du/dt)=-u^...

Differential Equations - The velocity v of a freefalling skydiver is well ...

Calculus - Solve the differential equation dy/dx = -xe^y and determine the ...

Differential Equations - Consider the differential equation: dy/dt=y/t^2 a) Show...

Differential Equations - Consider the differential equation: dy/dt=y/t^2 a) Show...

Differential Equations - Consider the differential equation: dy/dt=y/t^2 a) Show...

calculus - verify that y=c/x^2 is a general solution of the differential ...

Ap Calculus - Ok, I've been doing BC review tests to prepare for the AP exam. I ...

Calculus - Which of the following is a separable, first-order differential ...

calculus differential equation - Find in implicit form the general solution of ...