Find the exact value of Sin^-1(sin(13pi/15))

Answer 1

ummmhhh, wouldn't that just be 13π/15 ?

or, since the sine is + in both the 2nd or 1st quadrant, and
since 13π/15 is in quadrant II we could also have
π - 13π/15 = 2π/15

check with calculator, set to radians

enter:
13
x
π
÷
15
=
sin
=
2nd sin
= .41887902 which is 2π/15