(1)
â«[-â~+â]f(x)dx
=â«[0~Ï]Axdx
=ϲ/2·A
=1
â´A=2/ϲ
(2)
P(Ï/4â¤Xâ¤Ï/2)
=â«[Ï/4~Ï/2]2x/ϲ·dx
=x²/ϲ |[Ï/4~Ï/2]
=1/4-1/16
=3/16
(3)y=e^xåè°éå¢ï¼
xâ(0ï¼Ï)æ¶ï¼yâ(1ï¼e^Ï)
åå½æ°ä¸ºx=h(y)=lny
æ ¹æ®å
¬å¼å¾å°ï¼
yâ(1ï¼e^Ï)æ¶ï¼
fY(y)=f[h(y)]·|h'(y)|
=2lny/ϲ·1/y
=2lny/(ϲy)
â´fY(y)=
{2lny/(ϲy) yâ(1ï¼e^Ï)æ¶ï¼
{ 0 å
¶å®
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