## mathew0135 A particle moves on a straight line v(t)=sinwt cos ^{3} wt. find the position s(t) if s(0)=0. I've done this style of question before, but the two variables throw me off. I assume that u=cos(wt) but am unsure. one year ago one year ago

1. mathew0135

then du=-sin(wt)

2. mathew0135

-du=sin(wt)

3. mathew0135

$- \int\limits_{?}^{?} (u)^{3} du$

4. mathew0135

$-\frac{ 1 }{ 4 } (u)^{4} +c$

5. mathew0135

$- \frac{ (coswt)^{4} }{ 4 } +c$ then insert s(0)=0 so..... $- \frac{ (cosw(0))^{4} }{ 4 } +c$=0 ... but w is still an unknown...

6. mathew0135

woooooooo no idea whats going on....

7. mathew0135

unless -cosw(0)=0... then c=0... yeah i'm confused, doesn't seem right.

8. sirm3d

$\mathrm du=-w\cdot\sin wt\,\mathrm dt$