# Homework Help: Charge over a triangular region

1. Jan 21, 2010

### unknown_2

1. The problem statement, all variables and given/known data
-Given that $$\rho_{v}$$=6xy C/$$m^{2}$$, Calculate the total charge on the triangular region.

-the verticies of the triangle are: (0,0), (2,2) and (4,0)

2. Relevant equations

$$Q=\int_{s}\rho_{v}ds$$

3. The attempt at a solution

$$=\int^{4}_{0}\int^{-x+4}_{x}6xy dydx$$
$$=\int^{4}_{0}48x - 24x^{2} dx$$
$$=24x^{2}-8x^{3}|^{4}_{0}$$
$$=-128C$$

According to the textbook the correct answer is 32C

any help would be appreciated!
Thanks,

2. Jan 21, 2010

### kuruman

You got your integration limits mixed up. The maximum value for x is 2 m. Draw a picture and you will see why.