Question

HEY I have troubl with this equation ,can you solve it ?cos(2x)+cos(4x)=0.And THANKSS

Answer 1

Answer:

Apply the trig identity:

cos

4

x

=

2

cos

2

2

x

−

1

.

f

(

x

)

=

cos

2

x

+

2

cos

2

2

x

−

1

=

0

Call cos 2x = t, we have to solve the quadratic equation:

2t^2 + t - 1 = 0

tough question

Step-by-step explanation:

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