## Study23 3 years ago The equation of motion is $$\ s=2costy+3sint, t\le0$$. Find velocity/acceleration at time t. I took the derivative to find the velocity, but got 0...?

1. Dido525

is that 2cos(ty) ?

2. Study23

Good catch! That's supposed to be a t only.

3. Dido525

so $s=2\cos(y) + 3\sin(t) , t \le0$ ?

4. Dido525

Oops cos(t)

5. Dido525

Well the velocity at time t is just the derivative. Can you differentiate that?

6. Study23

@Dido525 I tried, but I got 0, which doesn't seem correct.

7. Dido525

Lets see:|dw:1351660147750:dw|

8. zepdrix

Oh that was a 2? :P sorry..

9. Study23

@zepdrix yup

10. Dido525

11. Study23

Would I add the derivates of each here? What happens to the constants?

12. Dido525

I just did the derivative for you O_o .

13. Study23

I suppose I was confused by the constants...

14. Dido525

Ohh. If you have constants out in from you take out the constant, take the derivative of the function and multiply the constant back in.

15. Study23

Ohh.Okay. I was getting the product rule confused with the addition one. So for the acceleration, I take the derivative of the derivative?

16. Dido525

Yep!

17. Study23

Okay!! Thanks so much!!!

18. Dido525

Welcome :) .