Let x, y are real numbers such that x²+2cos(y)=1. Find the range of x-cos(y).

(In reply to Solution by Jer)

Wasn't the question of the range of the function x-cos(y) where cos(y) = (1-x^2)/2? That's f(x) = x - (1-x^2)/2 = x^2/2 + x - 1/2, with a minimum of -1 at x=-1.

Posted by Charlie on 2021-09-20 14:11:26