I have to evaluate d/dx of (ln (5 – x^(2)))^(1/4) at x = 1

So, differentiating it I proceeded by y= (ln (5 – x^(2)))^(1/4) = ¼ (ln (5 – x^(2)))^(3-/4) * 1/(5 – x^(2)) * (-2x) = ¼ (ln (5 – x^(2)))^(3-/4) *(-2x)/(5 – x^(2));

By calculating this for x=1 gives me such a odd number, I am pretty sure I am wrong when I operate with the logarithmic values (since there I found after my mid-term that I have some gaps);

Could you take a look at it, and also give some links where I would be able revise some basic knowledge on logarithms?

Greatly appreciated,