How do you solve $4 cos x = 1 + 2 cos x$ $4\cos x = 1+ 2\cos x$ ?

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Answer 1 · 2017-03-05T10:32:39

$x = \frac{π}{3}$ $x=pi/3$

Rearrange to get all the $cos$ $cos$ over on one side.

$4 cos x = 1 + 2 cos x$ $4cosx=1+2cosx$

$2 cos x = 1$ $2cosx=1$

and now get it on its own by dividing by $2$ $2$ ,

$cos x = \frac{1}{2}$ $cosx = 1/2$

Now you can do an inverse function to find $x$ $x$ :

$cos x = \frac{1}{2} \to {cos}^{- 1} (\frac{1}{2}) = x$ $cosx = 1/2 -> cos^-1(1/2) = x$

$x = \frac{π}{3}$ $x = pi/3$

How do you solve 4cosx=1+2cosx4\cos x = 1+ 2\cos x?