- #1
schattenjaeger
- 178
- 0
I had a test this morning in cal 3 *crosses fingers* and I'm pretty sure I did well, but one of the questions was(I REALLY need somone to tell me how to do all the pretty math font stuff with symbols)
S=integral, for this problem the upper limit was y, lower limit was x)
f(x,y)=S(t^2+2t+3)^17 dt and then it asked for Fx and Fy, but that wasn't my problem
so u=t^2+2t+3, du = 2t+2dt
so you get (1/(2t+2))(u^18)/18, plug everything back in for u, and you get that decent ball of poo, then plug in the limits so you get [ball of poo with y in place of t] - [ball of poo with x in place of t], then just differentiate, for Fx the first part is 0, so it's -[more poo] and Fy is just [some more poo]-0?
Edit: Hah, I typed you instead of u
S=integral, for this problem the upper limit was y, lower limit was x)
f(x,y)=S(t^2+2t+3)^17 dt and then it asked for Fx and Fy, but that wasn't my problem
so u=t^2+2t+3, du = 2t+2dt
so you get (1/(2t+2))(u^18)/18, plug everything back in for u, and you get that decent ball of poo, then plug in the limits so you get [ball of poo with y in place of t] - [ball of poo with x in place of t], then just differentiate, for Fx the first part is 0, so it's -[more poo] and Fy is just [some more poo]-0?
Edit: Hah, I typed you instead of u