[(sin(3x) + cos(3x))/(cos(x)-sin(x))] = 1 + 2sin2x

i've been working on this for along time and still cannot prove it.

[(sin(3x) + cos(3x))/(cos(x)-sin(x))] = 1 + 2sin2x

i've been working on this for along time and still cannot prove it.

i've been working on this for along time and still cannot prove it.

- stapel_eliz
**Posts:**1628**Joined:**Mon Dec 08, 2008 4:22 pm-
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Since you've been working on this for some time, you've got some work you can show. Please reply with that, so we can see where you are. (You might be nearly to the solution!)[(sin(3x) + cos(3x))/(cos(x)-sin(x))] = 1 + 2sin2x

i've been working on this for along time and still cannot prove it.

Please start with your substitution on the left-hand side for the triple angles. You may have started with the sum identities and the double-angle identities, or perhaps you started right away with the

Then maybe you factored the and the

Either way, please start with the substitution. Thank you!