Verified answer

Ответ:

Объяснение:

a)

y=x*cosx

y'=(x*cosx)'=cosx-x*sinx.

б)

y=x²/(1+x)

y'=(x²/(1+x))'=((x²)'*(x+1)-x²*(x+1)')/(x+1)²=(2x*(x+1)-x²)/(x+1)²=

=(2x²+2x-x²)/(x+1)²=(x²+2x)/(x+1)²=x*(x+2)/(x+1)².