Question

ctg x - ((sin x) / (1 - cos x)) = -((1)/ (sin x))
тотожность

Answer 1

$ctgx-frac{sinx}{1-cosx} =-frac{1}{sinx} \ frac{cosx}{sinx} -frac{sinx}{1-cosx} +frac{1}{sinx}=0\ frac{(1-cosx)*cosx-sin^{2}+1-cosx }{(1-cosx)sinx} =0\frac{cosx-cos^{2}x+cos^{2} x-cosx }{(1-cosx)sinx} =0\frac{0}{(1-cosx)sinx} =0\0=0$

х ∈ R