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# Trigonometric Functions watch

1. I'm stuck on this one :s

prove the identity...

(sec A - tan A)(tan A + sec A)
_______________________ = (equivalent to) cot A + cosec A

cosec A - cot A
2. Use difference of two squares.
3. (Original post by mc_ragz)
I'm stuck on this one :s

prove the identity...

(sec A - tan A)(tan A + sec A)
_______________________ = (equivalent to) cot A + cosec A

cosec A - cot A
Have another try.

If you are really stuck, here is the solution:

1. Expand the numerator.

2. Using the identity:

3. Multiply the fraction by

4. Simplify the denominator by using the identity:

5. Answer: cot A + cosec A

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