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# Help with this question plz!!!! watch

1. It's a trigonometry question from c3

Give exact answers in terms of pi
2(1-cos2thetta) = tan thetta in the range of 0<thetta<pi

I think you use one of
cos^2thetta- sin^2thetta
1-2sin^2thetta
2cos^2thetta - 1
2. (Original post by jkljeril)
It's a trigonometry question from c3

Give exact answers in terms of pi
2(1-cos2thetta) = tan thetta in the range of 0<thetta<pi

I think you use one of
cos^2thetta- sin^2thetta
1-2sin^2thetta
2cos^2thetta - 1
Use the first one, as well as
3. the tanthetta on the right hand side would still be there
4. (Original post by jkljeril)
the tanthetta on the right hand side would still be there
Yeah so get rid off it by multiplying both sides by
5. what do i do now?

4sin^2 thetta cos thetta = sin thetta
6. (Original post by jkljeril)
what do i do now?

4sin^2 thetta cos thetta = sin thetta
Divide by , perhaps?

Spoiler:
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Usually we don't divide, but do you see why we CAN divide here?

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