-kt例2 f(t) = e8ktstdt则 L[f(t)] =ee081k+sotdts+k02025/8/15heuu-lxn
2025/8/15 heuu-lxn 11 例2 f(t) = 则 L[ f(t) ] = = kt e − − − 0 e e dt kt s t − + 0 ( ) e dt k s t = s + k 1
-kt例3 f(t)=A (e8ktstdtAe则 L[f(t)I=)e0A=s+k2025/8/15heuu-lxn
2025/8/15 heuu-lxn 12 例3 f(t) = A 则 L[ f(t) ] = kt e − = − − 0 Ae e dt kt s t
Akt(l-e-例4 f(t)= k80Akt)e-stt dt(1则 L[f(t) ] =k0oAAs+k)t dtVstdteekk001ACks+kSAs(s+k)2025/8/1513heuu-Ixn
2025/8/15 heuu-lxn 13 例4 f(t) = 则 L[ f(t) ] = = = = -
拉普拉斯变换表P404原函数f(t)象函数F(s)AA/s1/s2tAe-atA/(s+a)(1.e)A/s(s+a)AAe-at - e-bt )b-a(s+a)(s+b)2025/8/15heuu-Ixn
2025/8/15 heuu-lxn 14 拉普拉斯变换表 P404 原函数f(t) 象函数F(s) A A/s t 1/s2 Ae-at A/(s+a) ( 1 - e -at ) A/s(s+a) ( e-at - e -bt ) a A b-a A A (s+a)(s+b)
体内药量与时间-ktX=X.ex-t关系X.-kt-ktC=二C:eeV血药浓度与时间 C-t 关系152025/8/15heuu-xn
2025/8/15 heuu-lxn 15 e kt X X − = 0 e e kt kt C V X C − − = = 0 0 体内药量与时间 x-t关系 血药浓度与时间 C- t 关系