Best method to solve very slightly advanced equations.

[NewMC]

I alway seem to struggle with trying to find a correct and reliable way to do various things with this calculator. I've stuck with it since they were initially released and I intend to continue to carry it for daily use once I've finished my degree. The issue that I run into is that there are either not enough detailed instructions published or the methods I find do not work for slightly more advanced problems than those listed in the user's manual, etc.

So, I've manipulated an equation down to the following and I need to solve for alpha without random guesses and 40 different attempts, what is the best method for doing this? I've tried plugging this entire equation in the "Solve" application in various formats but the number it solves for is always about 0.5 to low or high, in which case I probably have an incorrect setting somewhere. I've also tried solve, csolve, and fsolve commands in CAS but I always get [[]] as a result. I'm assuming this is either an error or it's indicating that there are multiple answers, but where do I go from there? I have not been able to find what [[]] actually means.

Here is my equation: (sin(2*a)/(2*pi))-(a/pi)+0.75=0, where a=Greek letter alpha. The correct answer is 1.986 rad = 113.8 degrees.

Please help, thank you!!