展开 (5t^2e^{-8t}-e^{7t}cos(sqrt(5)t))(s)

解答

展开

(5 t^{2} e^{- 8 t} - e^{7 t} cos (5 t)) (s)

5 e^{- 8 t} t^{2} s - e^{7 t} s cos (5 t)

求解步骤

(5 t^{2} e^{- 8 t} - e^{7 t} cos (5 t)) (s)

= (s) (5 e^{- 8 t} t^{2} - e^{7 t} cos (5 t))

使用分配律:

a (b - c) = ab - a c

a = (s), b = 5 t^{2} e^{- 8 t}, c = e^{7 t} cos (5 t)

= (s) \cdot 5 t^{2} e^{- 8 t} - (s) e^{7 t} cos (5 t)

= 5 e^{- 8 t} t^{2} (s) - e^{7 t} (s) cos (5 t)

去除括号:

(a) = a

= 5 e^{- 8 t} t^{2} s - e^{7 t} s cos (5 t)

e x p an d (\frac{b}{a} (x - d) - f - c)^{3}

e x p an d \frac{11}{- 2}

s im pl i f y (a s + b) (s^{2} + s + \frac{5}{4})

e x p an d (x + y = 10,) - (z + y = 7)

s im pl i f y (\frac{3 m}{4} + \frac{1}{6}) (\frac{m}{4} + \frac{5}{6})