hello,

i have (dx/dt)^2 = (1/x^4) -1 and want to write an integral for t(x)...

(dx/dt) = +/- {x^2/[(1-x^4)^(1/2)]}

so t(x) = +/- integr of {x^2/[(1-x^4)^(1/2)]}

but the book says t = integr (from u=1 to =x) of {u^2/[(1-u^4)^(1/2)]}

can someone please help me see that the book has done here? thanks a lot!