1) f'(x) = 2(1-x)^(-1) = -2 / (1-x)^2
f'(-1) = -2 / (1+1)^2 = -2 / 4 = -1/2
2) f'(x) =
4х^4 * (-2x²)³= - 4x^4 * 8x^6= - 32x^14
Cvjnhb jndtns dj dkj;tybb
An=3n+5 => a1=3*1+5=8, a50=3*50+5=155
S50=((a1+an)/2)*n — формула
S50=((8+155)/2)*50 => S50=(163/2)*50 => S50=81,5*50 => S50=4075
(99^3-61^3)/38 + 99 * 61 = (99^3-61^3)/38 + 6039 = 25600