Question

Find g.s \[\cos 3x -\cos x + \sin 4x=0\]?

Answer 1

just continue

Answer 2

-2 sin2x sinx + sin 4x =0

Answer 3

then??

Answer 4

Ouch, sorry don't know

Answer 5

\[-2\ \sin 2x \sin x+2 \sin 2x \cos 2x=0\]\[\sin 2x(\cos 2x-\sin x)=0\]

Answer 6

\[\sin 2x=0\]or\[\cos 2x-\sin x=0 \rightarrow 2\sin^2 x+\sin x-1=0\]

im watching olympic

Answer 7

so sin x is 0.5 or x is 30....overall,x=0,30 degrees...

Answer 8

hey isnt this my that i posted earlier? :/

Answer 9

my question*

Answer 10

Yup

Answer 11

i also have doubts so i posted

Answer 12

sinx (2sinx +1) = sin 90

Answer 13

if\[\sin 2x=0\]\[2x=n\pi\] so \[x=\frac{n\pi}{2}\]
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if \[2 \sin^2 x+\sin x-1=0\] make a quadratic in terms of \(\sin x\) and enjoy

Answer 14

but your working looks nicer than mine..my one got ugly :/

Answer 15

Yup

Answer 16

wait wait i think you forgot about the cos3x

Answer 17

sin x = -1 or sinx = 1/2

Answer 18

@mukushla is that correct

Answer 19

yeah

Answer 20

thxx

Answer 21

np...:)