Presentation of working for residue life(stochastic processe)-img_1698.jpgPresentation of working for residue life(stochastic processe)-qns.jpg

Hi guys,

I'm really not sure whether my working is correct, especially the one whether I indicated with a question mark in my working. Im not sure if the integration can be transitioned in such a manner though I do know I got the correct ans. The question is referenced where ti follows a uniform distribution.
Would appreciate some input as my finals are next week. Thank you