Question 18
If $a$ and $b$ are positive real numbers such that $\frac1a+\frac1b=\frac1{a-b}$, find the value of $\left\lceil\frac ba\right\rceil$. Here $\lceil x\rceil$ denotes the smallest integer greatest than or equal to $x$. For example, $\lceil3.1\rceil=4$.