If f(x)=sqrt of (4sinx+2) then f'(0)=

We are given the function f(x)=sqrt of (4sinx+2)  and is asked to find the first derivative of the function when x is equal to zero. 

f(x)=sqrt of (4sinx+2) 
f'(x) = 0.5 (4sinx+2)  ^ -0.5 * (4cosx) 
f'(0) = 0.5 (4sin0+2)  ^ -0.5 * (4cos0) 
f'(0) = 0.5 (0+2)  ^ -0.5 * (4*1)
f'(x) = 0.5 (2)  ^ -0.5 * (4) 
f'(x) = -.1.65

Ithink it's b sorry if i'm wrong