Question

find solution for cos2x+cosx=0

Answer 1

\[\cos^2x+\cos x=0~~?\]
or
\[\cos2x+\cos x=0~~?\]

Answer 2

second one

Answer 3

2cos^2(x) + cos x -1 = 0

Answer 4

which is becomes,

2 cos^2 x + 2cos x - cos x -1 = 0

Answer 5

btw equation is cos2x+cosx=0

Answer 6

not ^2

Answer 7

yes, cos 2x = 2cos^2(x) -1

Answer 8

ok yeah

Answer 9

x = pi/4 & 1 more ans

Answer 10

@vijay what bout cos2x+sinx=0

Answer 11

in this case, think other way

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

Answer 12

and then?

Answer 13

acutally i got it thanks