(Extract from Cambridge O-Level Additional Mathematics June 2012 exam paper 1, question 3)

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I can't get rid of the 1+cosA when simplifying RHS, it keeps getting complex.

Help please.

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- Nov 6th 2012, 05:36 PMzikcau25Trigonometric Identities cosecA
(Extract from Cambridge O-Level Additional Mathematics June 2012 exam paper 1, question 3)

Show that

I can't get rid of the 1+cosA when simplifying RHS, it keeps getting complex.

Help please. - Nov 6th 2012, 05:52 PMtopsquarkRe: Trigonometric Identities cosecA
There can be easier solutions to the problem than the way I do it, but usually it works out not too bad.

I always replace things like cot(A) and cosec(A) (and whatever else) with sines and cosines. So for your identity we have

Generally the next step is to add fractions. So we have fractions...let's add them. The common denominator will simply be

So what's the LHS look like?

-Dan - Nov 6th 2012, 06:20 PMMarkFLRe: Trigonometric Identities cosecA
Another approach:

Try to derive the following:

- Nov 6th 2012, 06:45 PMSorobanRe: Trigonometric Identities cosecA
Hello, zikcau25!

Quote:

We have: .

. . . . . .

. . . . . .