4. y'=arccotx +x(arccotx)'=arccotx+x·[-1/(1+x²)]=arccotx-x/(1+x²)8.y'=2e^(x²)+2x[e^(x²)]'=2e^(x²)+2x e^(x²)· (x²)'=2e^(x²)+2x e^(x²)·2x=2e^(x²)+4x²e^(x²)
