Posted by **krista** on Thursday, May 6, 2010 at 11:12pm.

show that: (1-tanx)/(1+tanx)= (1-sinx)/(cos2x)

- Precal -
**drwls**, Friday, May 7, 2010 at 6:32am
Is the denominator on the right cos(2x) or cos^2x ? Neither seems to work.

If x = pi/4, the left side is 0 and the right side is 0.293/0 = infinity, if the denominator is cos 2x.

Therefore what you wrote is not an identity.

## Answer this Question

## Related Questions

- Trigonometry - Given that a^2+b^2=2 and that (a/b)= tan(45degee+x), find a and b...
- Trigo - Given that a^2+b^2=2 and that (a/b)= tan(45degee+x), find a and b in ...
- Trigonometry Check - Simplify #3: [cosx-sin(90-x)sinx]/[cosx-cos(180-x)tanx] = [...
- Mathematics - Trigonometric Identities - Prove: sinx + tanx = tanx (1 + cosx) ...
- precal - 1/tanx-secx+ 1/tanx+secx=-2tanx so this is what I did: =tanx+secx+tanx-...
- maths - trigonometry - I've asked about this same question before, and someone ...
- Mathematics - Trigonometric Identities - Prove: (tanx)(sinx) / (tanx) + (sinx...
- Pre-Calc - Trigonometric Identities Prove: (tanx + secx -1)/(tanx - secx + 1)= ...
- Math - Im really struggling with these proving identities problems can somebody ...
- Math please help quick - Which of the following are identities? Check all that ...