Question

Given y=sin(2x), then dy/dx at x=3 most nearly is:

A) 0.9600
B) 0.9945
C) 1.920
D) 1.989

My answer is D)1.9890 but in the solutions answer is
1.920.

Answer 1

the unit is probably radians not degrees

Answer 2

When I convert it to radians I get
http://www.wolframalpha.com/input/?i=1.989+degrees+to+radians

Answer 3

you don't have to convert,just set the mode in your calculator to radians
then you'll get 2*cos(6)=1.9203...