integral from 0 to infinity of ((ye^{-y/a}))/a

解答

\int_{0}^{\infty} \frac{( y e ^{- \frac{y}{a}} )}{a} d y

a

求解步骤

\int_{0}^{\infty} \frac{y e ^{- \frac{y}{a}}}{a} d y

计算不定积分:

\int \frac{y e ^{- \frac{y}{a}}}{a} d y = - e^{- \frac{y}{a}} (y + a) + C

带入上下限计算后得:

\int_{0}^{\infty} \frac{( y e ^{- \frac{y}{a}} )}{a} d y = 0 - (- a)

= 0 - (- a)

化简

= a

a re a y = x^{2} - 4 x, y = 2 x + 7

\int 3 ln (x^{2} - x + 4) d x

((x - 2)^{2} (x + 4))^{^{'}}

f (x) = 5 x^{2} e^{3 x}

t an g e n t y = (1 + 2 x)^{2}, (3, 49)