Differentiate.

Question

Differentiate.

zenmo · Answer

$$y = c cost + t^2sint$$

zenmo · Answer

$$ccost = c * cost$$

luigi0210 · Answer

I'm assuming "c" is a constant?

luigi0210 · Answer

For the first part of the equation, $\large c *cost$, you can just take the derivative and treat "c" as any number.

the second you'll need to use the product rule. Do you know how to apply the product rule?

zenmo · Answer

$$y' = [( (c)(-sint) + (1)(cost)) + ((cost)(t^2) + (2t)(sint))]$$

luigi0210 · Answer

Alright, since "c" is a constant, it is just a number. So it would just turn out as $\large -csint$

luigi0210 · Answer

Think of it as taking the derivative of something like $\large 5cost $

luigi0210 · Answer

The constant isn't affected in the process.

luigi0210 · Answer

Oh, alright, other than that, everything seems alright :) 

Should end up with something like:
 $\large \color{green}{y'=-csint+(t^2cost+2tsint )}$

zenmo · Answer

what happen to the 2nd term of cos(t)? 
$$y' = -csin(t) + \cos(t) + (t^2\cos(t) + 2tsin(t))$$

zenmo · Answer

happened*

luigi0210 · Answer

Since "c" is just a constant, that means it is not a function. And the derivative of any constant is 0. So technically that "cost" turned to 0, if you applied the product rule: 

$\Large y=ccost+t^2sint $ 

$\large y'=(-csint+(0)cost)+(t^2cost+2tsint) $ 

$\Large y'=-csint+t^2cost+2tsint$

zenmo · Answer

oh yea ... forgot about that, I was treating C as a variable

zenmo · Answer

okay, I got it now :)

luigi0210 · Answer

Good luck!

zenmo · Answer

Thanks! Is that a jinx cosplay btw?