Question

cos(2x)+1

Answer 1

i know cos(2x) = 1-2sin^2x

Answer 2

It's also 2cos²x-1. If you take this one, you'll lose the +1 at the end...

Answer 3

so it'll stay as 2sin^2x ?

Answer 4

No, cos(2x)+1 = 2cos²x-1+1 = 2cos²x

If you do it your way, you get:

cos(2x)+1 = 1-2sin²x+1=2-2sin²x, looks a little longer than 2cos²x!

Answer 5

i mean the answer will be \[2\sin ^{2}x\]

Answer 6

It is nopt, because if you use cos2x=1-2sin²x, you get:

cos(2x)+1 = 1-2sin²x + 1= 2 - 2sin²x

Answer 7

this is what i did \[\cos(2x)+1 = (2\sin ^{2}x-1)+1 = 2\sin ^{2}x\]

Answer 8

is this right?

Answer 9

No, because cos2x is NOT 2sin²x-1. It is 1-2sin²x!

Answer 10

Yoou cannot swith a-b into b-a. E.g. 5-2=3, and 2-5=-3, the outcomes are different.

Answer 11

ooh ok i get it

Answer 12

is cuz i had a formula that said that