Raspuns:
a) f' (x) = 5 * 3 x ^ 2 - (- sin x) + 1/x = 15 x^2 + sin x + 1/x
b) f' (x) = 5 + 7 * 2x + cos x - (x^1/5)'
f' (x) = 5 + 14 x + cos x - 1/5 x ^ (-4/5)
