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Help finding integral

Find indefinite integral of 1/(3+25x^2). I got sqrt(3)/15 arctan(5x/sqrt(3)). Back of the book said arctan(5x/sqrt(3)) / 5sqrt(3) was the answer...

March 10, 2014

3 Comments • Newest first

echan527

figured it out like 5 min after i posted this XD thanks though!

Reply March 11, 2014
Jaredragonx9

ur not a math whiz till you pull of double integrals

Reply March 10, 2014 - edited
pokeystick1

hi many books simplify sqrt(x)/x by multiplying both the top and bottom by sqrt(x) which is the same as multiplying by 1. in your case, sqrt(3)/3 shows up. multiplying top and bottom by sqrt(3) gives
[sqrt(3)*sqrt(3)]/[3*sqrt(3)]
= 3/[3*sqrt(3)] <-- the 3's cancel
= 1/sqrt(3)

your answer and the book's answer are equivalent.

Reply March 10, 2014 - edited