Ask a New Question

Question

simple question

how come
cos^2(x)-sin^2(x) = cos(2x)

where the identity cos(2x) come from?
thanks a lot
7 years ago

Answers

Reiny
recall cos(A + B) = cosAcosB - sinAsinB
you just have an application of this.

then ...
cos 2x = cos(x+x)
= cosxcosx - sinxsinx
= ....

7 years ago

Related Questions

I have a simple question: why does mgcl2 have a higher boiling point than ncl3?? I thought mgcl2... I have a simple question but am having a hard time understanding the explanation of an unreasonable... My question is very simple Why do metals when react with oxygen are called oxides like " magnesiu... Um.... My question is simple...What should you study the day b4 a Final? I have a very simple question that needs quite a simple answer: Are all human brains an equal size?... Hi simple question which of these have the dimension as length? A) a*t^2 B) v^2/2*a C) a*v... It's a simple question I am just so confused with this discrete probability distribution. The quest... a simple hwk question.. i don't understand what i need to do.. 1-butanol (shown below) burns in t... Simple question I may be over thinking 30. Gift Baskets: The Gift Basket Sore had the following p... This is just a simple question and all but when The sun's heat warms the air in the lower layer o...
Ask a New Question
Archives Contact Us Privacy Policy Terms of Use