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# Proving Identities Watch

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secx-cosecx = tanx+cotx
__________ = ________

tanx-cotx = secx+cosecx

Or written:

(secx-cosecx)/(tanx-cotx)=(tanx+cotx)/(secx+cosecx)
thanks
2. What have you done so far? post working then people can help you out!
3. Try writing them all out in terms of sines and cosines.
4. OK I will post my working now:

LHS:

(cosx^-1) + (sinx^-1)//(sinx/cosx) -(cosx/sinx)

= (sinx-cosx)//(sinxcosx)//sin^2 -cos^2//(sinxcosx)

then it's = sinx-cosx//sin^2 -cos^2
Lost here

also the // means all over
5. someone help, i was up all night
6. Combining the fractions in the numerator and denominator might help, then look for factors and other identities.
7. (Original post by Hopple)
Combining the fractions in the numerator and denominator might help, then look for factors and other identities.
yep, I tried that but still ended up at the same place.
It's confusing which to use as there's 4 different trig functions. thanks anyway
8. Only 2 trig functions there

Can you multiply through by anything to simplify things?
9. Hint: multiply through by (sin(x)*cos(x)). Simplify and rewrite in terms of sin and cos. Then rewrite 1 as sin^2x+cos^2x. Divide through by sinx*cosx. And you get the RHS. Not sure I have done this in the most elegant of ways -welcome to suggestions

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Updated: November 30, 2010
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