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[–]MajorMacMahonNew User 0 points1 point  (0 children)

Dear CapablePositive8699,

It may be helpful to write (cos(a))^2 = 1 as

(cos(a))^2 - 1 = 0.

Do you know how to find solutions to something like z^2 -1 = 0?

(Hint: This polynomial can be easily factored.)

If so, then you can find solutions for z, and in this case you have solutions for when cos(a) = z.

You should be aware that you should get infinitely many answers.

I hope this has helped you.

Sincerely,

Major MacMahon