Trigonometry Question from Cambridge Y11 (1 Viewer)

[lachy95]

Hey Guys,

Can anybody help me out with this - its bloody annoying. Unless I'm missing something? (But I'm pretty sure I'm not.)



Thanks heaps

(by the way its Cambridge Year 11/4F/16L)

 

[Nooblet94]

Change the cosec^2s into cot^2s and expand. Then change the 1+tan^2s into sec^2s, then multiply top and bottom by cos^2

 

[Hotisgood5]

Look at LHS and RHS. You'll see LHS with tan^2(c) and RHS with sin^2(c). The only way to turn tan^2(c) into sin^2(c) is by making it sin^2(c)/cos^2(c). As for for cosec^2(a) and coses^2(b), you turn them into cot^2(a) + 1 and cot^2(b) + 1. Once that is done, you multiply top and bottom by cos^2(c), expand the entire thing. After that you just turn cos^2 (c) into 1-sin^2(c). Hope that helps.