# Math Help - Dif EQ

1. ## Dif EQ

Verify that the function is a sol'n of the given differential equation:

t*dy/dt - y = t^2, y = 3t + t^2

So I worked with y = 3t + t^2

y' = 3 + 2t
y'' = 2

Then, t*dy/dt - (3t + t^2) = t^2 .. so if it did work, that means t*dy/dt = 3t, but I don't seen how.

2. Originally Posted by Ideasman
Verify that the function is a sol'n of the given differential equation:

t*dy/dt - y = t^2, y = 3t + t^2

So I worked with y = 3t + t^2

y' = 3 + 2t
y'' = 2

Then, t*dy/dt - (3t + t^2) = t^2 .. so if it did work, that means t*dy/dt = 3t, but I don't seen how.
Why did you take the second derivative?

Subbing the solution in I get:
$t \cdot (3 + 2t) - (3t + t^2) = t^2$

$3t + 2t^2 - 3t - t^2 = t^2$

$t^2 = t^2$ (Check!)

-Dan