Posted by **Momo** on Sunday, October 18, 2009 at 1:57pm.

Solve this equation algebraically:

(1-sin x)/cos x = cos x/(1+sin x)

---

I know the answer is an identity, and when graphed, it looks like cot x. I just don't know how to get there. I tried multiplying each side by its conjugate, but I still feel stuck. This is what I have so far:

cos^2(x)/cos x + sin x =

cos x - sin x/cos^2(x)

...but I'm not really sure how to get to the answer. Help please?

Thank you!

- Math -
**jim**, Sunday, October 18, 2009 at 2:24pm
Do you mean solve it or prove it?

It is an identity, so there really isn't a specific solution: it's true for all x.

I suggest you try reformatting as

(1-sin x)/cos x - cos x/(1+sin x) = 0

Then bring both fractions to the common denominator (cosx)(1+sinx), and I think you'll recognise the numerator you're left with!

- Math -
**Momo**, Sunday, October 18, 2009 at 2:44pm
Ok, I worked it out, and so far i have this:

cos^2x - cos x - sinxcosx /

cosx + sinxcosx

Now I just need some help with reducing?

- Math -
**jim**, Sunday, October 18, 2009 at 3:01pm
Um, no. Wrong turn somewhere. It's a LOT simpler than that.

Your numerator will be :

(1-sinx)(1+sinx) - cos^2x

## Answer This Question

## Related Questions

- algebra - Can someone please help me do this problem? That would be great! ...
- Pre-Calculus - I don't understand,please be clear! Prove that each equation is ...
- Pre-Calculus - Prove that each equation is an identity. I tried to do the ...
- TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...
- Trigonometry - Please review and tell me if i did something wrong. Find the ...
- Precal - I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A...
- trig - it says to verify the following identity, working only on one side: cotx+...
- Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...
- Trigonometry - Prove the identity sin(x+y+z)+sin(x+y-z)+sin(x-y+z)+ sin(x-y-z...
- verifying trigonometric identities - How do I do these problems? Verify the ...

More Related Questions