Can you integrate this please?

Question

I think I'm gonna go nuts. I'm trying to integrate this but always getting the wrong answer. I've done it 5 times already. Ok here it is:

Double-integrate this from 0 to 0.4 (for both x and y):

2/5(2x+3y)dxdy

The answer's supposed to be 0.64 but I keep getting 0.128. If you got the right answer, can you please walk me through every step of the integration process in detail? I'll give best answer! :)

Sorry, the answer's supposed to be 0.064

Sorry, let me clarify the function:

(2/5)(2x+3y)dxdy

P D thanks a lot for your answer! Exactly what I was looking for!

Answer 1

Your function is too vague. Is it 2/[5(2x+3y)] or
(2/5)(2x+3y)

Answer 2

(2/5)(2x+3y) dxdy = SS [(4/5)x + (6/5)y dxdy]
the way i do it is do the x integrate first.

so SS (4/5)x + (6/5)y dx = (2x^(2))/5 + (6/5)xy.
= (2(.4)^2))/5 + (6/5)( .4)y
= .064+.48y

NOW use that answer to integration the y portion
SS .064 + .48y dy = .064y+ .48y^(2) /2
= .064y + .24y^(2)
= .064(.4) + .24(.4)^2
= .064