lim ( (1+x)^(1/3) - (1-x)^(1/3) )/x
x→0

lim ( (1+x)^(1/2) - (1+x^2)^(1/2) )/( (1-x^2)^(1/2) - (1-x)^(1/2)
x→0
どなたかお願いします。