Thank you soo much for the reply and help. I basically just split it up into [e*(x^2)]/2 + [e*-(x^2)]/2, initially to try and integrate.
After using the way you suggested and evaluating it I got 0 again.
Not sure if I correctly went about the rest of the integration to get 0 though.
But from integrating cosh(x^2).dx for x between 0 and 3 i got:
First part: [sinh(x^2) / 2x] for x=0 and x=3, which led me to sinh(9)/6 - 0.
Second part: From integating (x/3)cosh(x^2).dx for x between 0 and 3 i got (1/6)sinh(9) - (1/6)sinh(0) = (1/6)sinh(9) - 0 = (1/6)sinh(9).
Hence subtracting the second integral from the first gives me 0 again.
Does that look right? Thanks again!