为什么if函数不检查整数呢?

So I'm trying to do a recursive calculation with time-steps h, and the time is t. I want the second if-function (in the while-loop) to check if the time t is an integer. It works for the first loop when t=9, but after that it ignores when t=8,7,6,... and so on. And right now I just don't understand why. I would be very grateful for any help or ideas!So I'm trying to do a recursive calculation wit