Am i approximate 2 ^ (1/5) correctly with newton's method? (assuming x0 = 1, find x1,x2)

since 2 ^ (1/5) = x

i get the function f(x) = x^5-2

f'(x) = 5x^2

therefore, x0 = 1

x1 = 1- f(1)/f'(1) = = -2/5

but when i find x2 = -2/5 - f(2/5)/f'(2/5) = -18.67

i get a large negative number for x2 but x1 is like -2/5. Is this correct? The difference is so large :/