Question

Решите методом замены переменной1)tgx- ctgx=02)-2sin^2x-cosx+1=03)2sinx+cos^2x-1=0

Answer 1

$1. frac{sinx}{cosx} - frac{cosx}{sinx} = frac{sin x^{2}+ cos x^{2} }{cosx sunx} = frac{1}{cosx sinx} 2. -2sin^{2}x - cosx+sin^{2}x + cos^{2}x= - sin^{2}x+cosx 3. 2sinx+cos^{2} 2x- sin^{2}x+cos^{2}x$