Question

I need step by step instruction on another precal/trig problem to get an answer :/ Please help? Click on attached

Answer 1

First draw a graph, you know its in the 3rd quardrant and that cosA=-2/5. Using SOH CAH TOA, you can get adjacent=-2 and hyp=5.

Answer 2

Mkay, makes sense so far

Answer 3

Then using Pythagorus' theorem, you can figure out the left side of the triangle. And again using SOH CAH TOA, You just put in the value you found for opposite: sinA=opp/hyp

Answer 4

Get it?

Answer 5

Yea, just a second

Answer 6

Sorry, I kind of messed up the question. First, find angle A, then you can divide it by 2, and find sin cos and tan of A/2.

Answer 7

Is angle A 23.58 degrees?

Answer 8

Can you clarify?

Answer 9

Kind of, but you have to remember it's in the 3rd quadrant (so add 90 deg). The question is kind of confusing. I'm assuming all you have to do is find cos(A/2), sin(A/2) and tan(A/2). Starting by finding A, then, you just divide A by 2 (A/2) and then use your calculator to find those other angles.

Answer 10

Well in the end I only need sin(A/2)

Answer 11

Ok, thanks! I followed step by step and my ending result: sin(A/2)= 0.836.
Is this correct?

Answer 12

That's what I got, yep.