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# Cosine graph watch

1. Cos theta= (square root 3)/2
Solve this equation, giving all solutions in radians between -2pi and 2pi
2. (Original post by 6kh7741)
Cos theta= (square root 3)/2
Solve this equation, giving all solutions in radians between -2pi and 2pi
What have you tried? What method do you use to solve something that looks like this?
3. (Original post by 6kh7741)
Cos theta= (square root 3)/2
Solve this equation, giving all solutions in radians between -2pi and 2pi
theta=arccos(0.5root3), gives a solution between 0 and pi. cos (theta) = cos (-theta) and cos (theta) = cos (2pi-theta)
4. Make theta the subject so that you get one of the solutions, then use CAST or the graph method to find the other values between the asked range.
I'll start you off:
Theta = cos^-1.......

EDIT: Also ensure that your calculator is in radians - easy mistake everyone makes!!

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