Attachment 30336

how does [cos(4x)-1] become [1- 2sin^2x -1] = 2sin^2x ?

which really means cos(4x) becomes 1-sin^2x

which trig identity does this use?

Printable View

- Mar 8th 2014, 06:28 AMkingsolomonsgravelimits at infinity of trigs
Attachment 30336

how does [cos(4x)-1] become [1- 2sin^2x -1] = 2sin^2x ?

which really means cos(4x) becomes 1-sin^2x

which trig identity does this use? - Mar 8th 2014, 06:39 AMPlatoRe: limits at infinity of trigs
- Mar 8th 2014, 07:15 AMkingsolomonsgraveRe: limits at infinity of trigs
This forum is really quite amazing. As amazing as mathematics is, I think the people who love it and create it are equally inspiring.

I would bet, statistically speaking, that the level of generosity among mathematicians/math nerds (at least with respect to sharing mathematics) is much higher than that of the general population. Just look at this forum and others like it, or Khan academy and PatrickJMT (both of whom voluntarily post hundreds if not thousands of math videos on youtube for free)!

Thanks much!!!