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34 votes
please help me solve this, I got: pi/2, 4pi/3, and 5pi/3. maybe i'm missing a solution or didn't eliminate one properly? because it was wrong. thank you for any help!

please help me solve this, I got: pi/2, 4pi/3, and 5pi/3. maybe i'm missing a solution-example-1
User Anthony Hessler
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2.5k points

1 Answer

8 votes
8 votes

The expression is given as


\sin 2x=\sqrt[]{3}\text{ cosx}

Simplify the expression by using the identity

sin2x=2 sinx cosx.

Substitute the identity in the expression above


2\sin x\text{ cosx=}\sqrt[]{3}\cos x
2\sin x\cos x-\sqrt[]{3}\cos x=0
\cos x(2\sin x-\sqrt[]{3})=0
\cos x=0,\sin x=\frac{\sqrt[]{3}}{2}

For cosx =0,


x=(\pi)/(2),(3\pi)/(2)

For


\sin x=\frac{\sqrt[]{3}}{2}
x=(\pi)/(3),(2\pi)/(3)

Hence the solution of x for the given interval [0,2pi) is


x=(\pi)/(2),(3\pi)/(2),(\pi)/(3),(2\pi)/(3)

User Muhammad Younus
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3.0k points