Saturday

April 19, 2014

April 19, 2014

Posted by **Marissa** on Sunday, May 11, 2008 at 6:27pm.

The choices are

a) -3x^2sinx^3cos(cos x^3)

b) -3x^2sinx^3sin(cos x^3)

c) -3x^2cosx^3sin(cos x^3)

d) 3x^2sin^2(cos x^3)

I'm not exactly sure where I should start.

Should I begin with d/dx of sin? Or do the inside derivative first...and do I have to separate cos and x^3 as well?

- Math, derivatives -
**Count Iblis**, Sunday, May 11, 2008 at 6:44pmThis is a multiple choice question and then the way you should attack the problem should be different than if you were asked to find the derivative of sin[cos(x^3)]

What you do is you use the chain rule, accrding to which the derivative of

sin(f(x)) = cos(f(x)) f'(x)

Without calculkating anything, you immediately see that b) c) and d) cannot be right, so a) must be right.

The prefactor -3x^2sin(x^3) is indeed the derivative of the argument of the sin. You only have to notice that it looks correct and then move on to the next question. In a test you can be given many multiple choice question and then the teacher will test if you can spot the correct answer within seconds.

**Related Questions**

Cos-Derivative - y= (cos^3 x) (cos 3x) I got -3 sin(3x) cos^3x - 3 sin(x) cos (...

Precal - I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A...

Trig check my work please? - 8 sin²(3x) cos²(3x) = 2 [2 sin(3x) cos(3x)]² = 2 [...

pre-cal - Simplify the given expression........? (2sin2x)(cos6x) sin 2x and cos ...

Trigonometry - Find the general solution of the following equation. sin (5x) = ...

Urgent math - If f(x, y, z)=sin(3x-yz), where x=e^(t-1), y=t^3, z=t-2, what's df...

tigonometry - expres the following as sums and differences of sines or cosines ...

Derivatives - what is derivative of sin^2 (3x-1)^2 ? dy/dx (sin^2 (x))= 2 sin x...

Math - the original problem was: Solve: sin(3x)-sin(x)=cos(2x) so far i've ...

Calculus 12th grade (double check my work please) - 1.)Find dy/dx when y= Ln (...