How many solutions does the equation `x=100 sinx` have in the closed interval `[0,3pi]` ?

Explanation

The solution of the equation is obtained by the intersection of two graph `y=x/100` and `y=sinx` in the interval `[0,3pi]`.

As long as `y=x/100` cuts the curve `y=sinx`, we will keep getting solutions.
As `y le 1` (i.e., `sinx le 1`)
`rArr x/100 le 1`
`rArr x le 100`
In the interval `[0,3pi]`, we have
Number of solutions in `[0,pi]=2`
Number of solutions in `[2pi, 3pi]=2`
Hence, total number of solutions in `[0,3pi]=4`.