2Sin tita+2Cos tita=1.5.find tita
That's theta not tita
For ease of typing, I'll just use x.
2sinx + 2cosx = 1.5
sinx + cosx = 3/4
Now, since sin 45° = cos 45° = 1/√2,
sinx + cosx = √2 sin(x+45°)
Now we have
sin(x+45°) = 3/(4√2) = 0.53033
x+45° = 32°
x = -13°
You probably want values in [0,360°), so
x = 193° or 347°