It is proved that the equation x = asinx + B, where a > 0 and b > 0 have at least one positive root and it does not exceed a + B

It is proved that the equation x = asinx + B, where a > 0 and b > 0 have at least one positive root and it does not exceed a + B

Let f (x) = x-asinx-b
Then f (0) = - B0. According to the existence theorem of zeros, f (x) = 0 has at least one zeros X in the interval (0, a + b)_ 0, and X u 0