trig representation

[DrD]

The original integral:
calculator:=int(x*sec(x^2),x);

Substitution:
let u=x^2; then:
du=2xdx
dx=du/2x

The integral becomes:
(1/2)*∫(x*sec(u),u)
oopsie correction: (1/2)*∫(sec(u),u) my copy and paste error, sorry! Thanks Arno!

pencil:=1/2)*ln(ABS(sec(x^2)+tan(x^2)));

Parisse suggested:

Quote:The best way to check a result obtained by hand with the calc answer is check if simplify of the difference returns 0.

calculator-pencil ≠0
(calculator==pencil) ==> 0, false

This test fails, as does the equivalence operators. Taking the difference, simplified or not, between the calculator result, and the manual result, isn't zero. affirm({calculator, pencil})?