Ok. Unless you made a typo, this question relies on one principle of the sine function. And that is... what is the magitude of the MAXIMUM value of sin(x), where x can be any real number?

ANSWER....

1! The sine function will periodically go between -1 and 1 forever and ever. It can never be more than 1. So I would say the answer to your question is that a has 0 solutions.

Jameson