А) y'=[1/(x+√(x²-1))]*(1+2x/2√(x²-1))=(1+x/√((x²+1))/(x+√(x²-1))
б) siny+xy'cosy+y'sinx+ycosx=0
y'(xcosy+sinx)=-siny-ycosx
y'=-(siny+ycosx)/(xcosy+sinx)
в) y'=[(e^x)(x+4)^4/√(5x-1)]'={[(e^x)(x+4)^4+4(e^x)(x+4)^3]√(5x-1)-(e^x(x+4)^4)(5/2√(5x-1))}/(5x-1)