Question

please help... will fan and give medal
solve the equation cos 2θ+3 sin 2θ=2, for 0◦<θ<90◦.

Answer 1

expand cos2theta

Answer 2

can you do the steps pls ??

Answer 3

\[\cos2\theta = \cos ^{2}\theta - \sin ^{2}\theta\]

Answer 4

can you do steps further to get the answer please ?

Answer 5

also use sin 2O = 2 sin O cos O

Answer 6

yeah @cwrw238 plz help me

Answer 7

so we have cos^2 O - sin ^2 O + 6 sin O cos O - 2 = 0

Answer 8

got it.. next ?

Answer 9

this is not as straight forward as i thought..

Answer 10

yeah i know

Answer 11

i thought we might get a quadratic equation which we could easily solve but we cant

Answer 12

yeah it wont end in a quadratid

Answer 13

one way would be to replace cos^2 x by 1 - sin^2 x and cos x by
sqrt(1 - sin^ 2 x) which would be a bit messy....

Answer 14

it will be too long i think

Answer 15

@phi what do you think? could you help ?

Answer 16

well you can do this problem by another way

Answer 17

please help

Answer 18

consider a triangle with base of 3 units and height of 1 units

Answer 19

the triangle will be a right angled triangle

Answer 20

yes

Answer 21

now the hypotenuse will be \[\sqrt{10}\]

Answer 22

and the angle 71.6