solve: cos2theta?

2 ⤊

2007-05-15 19:49:07 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

cos2theta

or=>cos^2 theta - sin^2theta

or=>1-sin^2theta

or=>2cos^2theta-1

2007-05-18 21:11:02 · answer #1 · answered by Anonymous · 2⤊ 0⤋

cos 2x
= cosÂ²x - sinÂ²x

= (1 - sinÂ²x) - sinÂ²x
= 1 - 2.sinÂ²x

= 1 - 2.(1 - cosÂ²x)
= 2cosÂ²x + 1 - 2
= 2.cosÂ²x - 1

2007-05-16 02:56:18 · answer #2 · answered by Como 7 · 0⤊ 0⤋

You cannot solve something unless you knwo what it's equal to.

2007-05-16 02:56:36 · answer #3 · answered by Brian R 2 · 0⤊ 0⤋