Difference between sinx to sin2x?

Question

What does the 2 after the sin do? I kind of forgot....

Answer 1

Well, if it is written just the way you typed it, then the second expression means the sine of TWICE the angle given by x.  

Example: x = 45 degrees

sinx = sin(45) = root 2 over 2

sin2x = sin (2 * 45) = sin(90) = 1