# Derivatives halp

1. Nov 4, 2007

### ggcheck

1. The problem statement, all variables and given/known data
find the derivative using the appropriate rules

y=sin(cos(sinx))

3. The attempt at a solution

d/dx[sin(cos(sinx))] = [cos(cos(sinx))] * [-sin(sinx)] =

-cos(cos(sinx))(sin(sinx))

Is that right?

It doesn't feel right.

2. Nov 4, 2007

### rock.freak667

Try making an extended chain rule...let t=sinx and then u=cost ...and then differentiate and use the chain rule

3. Nov 4, 2007

### rocomath

you're very close!!! 1 more angle

4. Nov 4, 2007

### ggcheck

is the first factor done? and -sin(sinx) needs more?

5. Nov 4, 2007

### ggcheck

something like this: y= sinu ; u=cos(t) ; t=sinx

d/du[y] * d/dt * d/dx[t] ?

Last edited: Nov 4, 2007
6. Nov 4, 2007

### ggcheck

= cosu * (-sint) * cosx =

-sin(sinx)*cos(cos(sinx))*cosx ??

7. Nov 4, 2007

### rock.freak667

well the chain rule is correct...so I would assume that it is correct

8. Nov 4, 2007

### ggcheck

It wouldn't be uncommon for me to apply a rule incorrectly.

9. Nov 5, 2007

### rock.freak667

Well it is correct