Calculus
posted by Tracy .
evaluate the integral of
dx/square root of 98xx^2

98xx^2 = 25  (16 + 8x + x^2) = 3^2  (x4)^2
Integral sqrt(a^2  u^2) du = u/2 * sqrt(a^2  u^2) + a^2/2 arcsin(u/a)
just plug in a=5 and u=x4 and plug away.
This is a standard trig substitution and integration by parts. 
typo: 5^2 not 3^2

Go on: wolframalpha dot com
When page be open in rectangle type:
integrate dx/sqrt(98xx^2)
and click option =
After few seconds when you see result click option: Show steps