Find sin x/2, cos x/2, and tan x/2 from the given information.
cos x = −15/17, 180°

Question

Find sin x/2, cos x/2, and tan x/2 from the given information.
cos x = −15/17, 180° < x < 270°

sin x/2=

cos x/2=

tan x/2=

anonymous · Answer

How do you do this problem? I really need help with this!

anonymous · Answer

Use the three formulas...the formulas all have cos x in them and you know what cos x (-15/17). Only note that x is a 3rd quadrant angle, so 1/2 of x would be a second quadrant angle (where sin is positive, and cos/tan are negative).

anonymous · Answer

I am unsure of what cos x (-15/17) is! I can plug the numbers into the equations and everything I just don't understand what cos x (-15/17) is

anonymous · Answer

You do not have to know that.

In the formulas, there is an expression cos x. Just substitute -15/17 for cos x. It is straightforward.

anonymous · Answer

Why not do the sin (1/2  x)...show me your work, and I can see if you have done it correctly.

anonymous · Answer

sin (x/2)=  |dw:1383758855796:dw|