PDF《第2章习题及解答》

05 1

5 syms t f=0.5*(1-cos(5*t));

F=laplace(f) F = 1/2/s-1/2*s/(s^2+25) (b) t t f t

314 cos e ) (

2 .

0 ? = syms t f=exp(-0.2*t)*cos(314*t);

F=laplace(f) F = (s+1/5)/((s+1/5)^2+98596)

3 (c) f t t ( ) sin( ) = +

5 3 π syms t f=sin(5*t+pi/3);

F=laplace(f) F = (1/2*s*3^(1/2)+5/2)/(s^2+25) (d) f t t e t

2 3 syms t f=t^2*exp(-3*t);

F=laplace(f) F = 2/(s+3)^3 解毕.

4 2-4 求出题图所示时间信号 f t ( )的拉氏变换F s . ( ) t0

0 f(t) t t0 π/ω

0 f(t) t A 半波正弦 -M

0 f(t) t M T 占空比=ηT 0