How do you solve cos(1/2x)=-sqrt3/2cos(12x)=−√32?

1 Answer
KillerBunny
Oct 3, 2016

x = 5/3pi+4pix=53π+4π

or

x = -5/3pi+4pix=−53π+4π

Explanation:

Since it's a known fact that the cosine equals -sqrt(3)/2−√32 for an angle of \pm 5/6 pi±56π, we knot that the argument of the function must be one of the two angles.

In this case, the argument is x/2x2, so we have

x/2 = 5/6pi+2pix2=56π+2π

or

x/2 = -5/6pi+2pix2=−56π+2π

These solutions lead to

x = 5/3pi+4pix=53π+4π

or

x = -5/3pi+4pix=−53π+4π

Related questions
See all questions in Solving Trigonometric Equations
Impact of this question
3337 views around the world
You can reuse this answer
Creative Commons License