Question

y= sin 2x-x find y' (pi/2)
a. -3
b. -1
c. 0
d. 1
e. undefined

Answer 1

y=sin2x-x
y'=2cos2x-1
y'=2cos(2*pie/2)-1
y'=2(-1)-1
y'=-3 (ans)

Answer 2

why is there a 2 in front of cos2x

Answer 3

coz it's a differentiation rule y=cosmx
dy/dx=-msinmx