i got @=n(pi), @=n(pi)+(-1)^n(pi/2), @=n(pi)+(-1)^n(-pi/2)
the answer is @=npi/2
if you take a look closely they're both the same answer...
but in any case you're both wrong
the answer should be x = n.pi +- pi/4
and sin3x=sin2x, i thought it would be quite simple, like...