http://img443.imageshack.us/img443/701/identityuf5.png

I've tried many things, can't seem to work it out. Thank you!

Printable View

- Nov 6th 2007, 01:52 PMJeavusCan someone help me solve this identity? :)
http://img443.imageshack.us/img443/701/identityuf5.png

I've tried many things, can't seem to work it out. Thank you! - Nov 6th 2007, 01:58 PMKrizalid
Did you tried simplifyin' the LHS?

Factorise. - Nov 6th 2007, 01:59 PMJeavus
Yes, I've been working with the left hand side.

I've tried a lot of things. - Nov 6th 2007, 02:01 PMKrizalid

Does that make sense? - Nov 6th 2007, 02:13 PMJeavus
How does sin^3theta = (1+costheta)(1-costheta)?

- Nov 6th 2007, 02:20 PMangel.white

1. because , substitute that into

2. Common denominator of the fractions in the numerator

3. combine fractions in the numerator

4. simplify (dividing a fraction by something means multiplying by it's inverse):

5. factor out in the numerator

in the numerator and denominator cancel eachother out

6. Multiply the numerator and the denominator by

7. FOIL the numerator:

8. Using the formula see that and substitute that into the equation

9. is in the numerator and the denominator, so cancel them out

- Nov 6th 2007, 04:00 PMSoroban
Hello, Jeavus

Quote:

How does sin^3theta = (1+costheta)(1-costheta)?

Quote:

Originally Posted by**Krizalid**

- Nov 6th 2007, 04:24 PMJeavus
Thank you all so much. :)