Wednesday

November 26, 2014

November 26, 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.

**Answer this Question**

**Related Questions**

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

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

Trig - prove the identity (sinX)^6 +(cosX)^6= 1 - 3(sinX)^2 (cosX)^2 sinX^6= ...

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

Math - Solving Trig Equations - What am I doing wrong? Equation: sin2x = 2cos2x ...

Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...

calculus - Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x...

Calc. - Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x ln...

Math - Calculus - The identity below is significant because it relates 3 ...

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