Question

Solve for x: sin^2x+cos2x-cosx=0

Answer 1

i just tried yours and it's hard lol

Answer 2

ik haha its freaking impossible
stupid summer assignment :/

Answer 3

do u know the formula for sin ^2 x and cos 2x in terms of cos x and/or cos ^2 x ?
and its easy :)

Answer 4

lol im trying to solve it right now

Answer 5

\[\cos^2θ −\sin^2θ\] do we have to use that?

Answer 6

@hartnn

Answer 7

The answer is \[x=2\pi n\]

Answer 8

yes,u can use that,but that still contains sin^2 theta,can u convert that also in cos ^2 theta?

Answer 9

no you can't it'll cancel though.. hold on let me do it on paper and then ill scan it.

Answer 10

\[n\]

Answer 11

convert sin^2x into cos^2x

Answer 12

\[n\]

Answer 13

is this in terms of degrees or radians?

Answer 14

radians

Answer 15

okay im gonna scan my work now, i think it's right.

Answer 16

is there a range?

Answer 17

\[0 \le x <2\]

Answer 18

thats the domain

Answer 19

2pi^

Answer 20

im not sure if it's right.

Answer 21

i thinkit is right

Answer 22

i think so i too lol i don't know.

Answer 23

yes its right,but 2pi should also be the answer
0,pi,2pi

Answer 24

right

Answer 25

no there is no 2 pi

Answer 26

nvrmd ur right my bad :P

Answer 27

but r u sure cos2x= cos^2x-sin^2x

Answer 28

ohh x<2pi
ok then 2pi will not be answer
yes that formula is correct

Answer 29

ok is that like an identity or something?

Answer 30

yes,standard formula,which u can prove

Answer 31

ok thx! do u have idea what its called?

Answer 32

or is it just called standard formula? lol