3. If u = (x2+9)1/2 and v = 3x2-2x, then what is du/dv as a function of x?

A. 1/(4(3x-1)(x2+9)1/2) for x ¹ 1/3

B. (3x-1)/(2(x2+9)1/2)

C. (2x(3x-1))/(x2+9)1/2

D. x/(2(3x-1)(x2+9)1/2) for x ¹ 1/3

 

Solution: The answer is D

 

First find du, by taking the derivative of u with respect to x.

Multiply both sides by dx so that,

Similarly, find dv.

Thus, dividing du by dv. yields,