I like proving but this one, I got stuck because of time pressure. It was the last question and I was hurrying since I only got 5 mins left. I didn't get to finish my solution so I may have gotten a few points off it.
here it goes:
1/cos^2B = [cosB sin2B - sinB cos2B]/cosB sinB
so what I did first was:
1/cos^2B = cos(B+2B)/cosB sinB
then I got stuck so I repeated it then came out with:
1/cos^2B = sinB - cosB/cosB sinB by subtracting the functions (idk if that's allowed) then I tried to break that down. I am still stuck.
anyone who can help me on how the sol'n goes??