Производная f(x)=(x-1) √(x^2+1), если х=0

F`(x)=(x-1)`*√(x²+1)+(x-1)*(√(x²+1))`=1*√(x²+1)+(x-1)*2x/(2√(x²+1))=
=√(x²+1)+x(x-1)/√(x²+1)=(x²+1+x²-x)/√(x²+1)=(2x²-x+1)/√(x²+1)
f`(0)=(0-0+1)/√(0+1)=1/1=1