math please help
posted by Sushmitha .
use an inverse trig function to write theta as a function of x
(There is a right triangle drawn.
The hypotenuse is 2.
Theta is the angle between the base and the hypotenuse.
The base/adjacent side of theta is labeled(x + 1)
The side opposite theta does not have a value.)
Use an inverse trig function to write theta as a function of x:
a) theta = sqrt [4  (x + 1)^2] all divided by 2
b)theta = arccos [(x + 1)/2]
c)theta = arctan[(x + 1)/2]
d)theta = arcsin [2/(x + 1)]
How do I do this? I'm leaning towards B, the inverse cosine because only the adjacent side and hypotenuse are given. The opposite side is not given, and there is already a variable x in the given adjacent side.
Am I on the right track? If not, please explain. Thank you.

Leaning? Lord, solve the triangle.
so cosine Theta=(x+1)/2
So lean on B. 
find sin 20,cos 20 and tan 20 given that cos 0<=4/5 and 90 degrees<0<180 degrees