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portage 1) 1 + sinx = cosx where -180 < x < 180 (Provide the general and particular solutions)
square both sides, change cos^{2}x to 1 - sin^{2}x, and solve the resulting quadratic in sinx ... don't forget to check for extraneous solutions
2) Prove
(cosx/2 - sinx/2)^2 = 1 - sinx
square the left side, then use the Pythagorean identity and the double angle identity for sine
3) Prove
sin2A = 1 - 2sin^2 (45 - A)
use the difference identity for sine to find sin(45-A) , square the result, then use the double angle identity for sine.