Question

integral of 1/(x^2sqrt(4x+1))?
I tried trig substitution since it looks like sqrt(x^2+a^2) with x=2sqrtx and a = 1

Answer 1

x=a*tan (theta)

Answer 2

I worked this down to 8*integral of [tan(theta)sec^2(theta)/[tan^4(theta)sec(theta)]

Answer 3

simplify tangent and secant?

Answer 4

is that 4x+1 inside, or 4x^2+1?

Answer 5

I don't think trig sub works here like that, check your " it looks like sqrt(x^2-a^2) with x=2sqrtx and a = 1" idea again.

Answer 6

4x+1, otherwise I think I could get it

Answer 7

???, but (2sqrtx)^2 = 4x and 1^2 = 1.

Answer 8

I guess its called radicals instead of trig sub in my math book, may have gotten terms confused.

Answer 9

It was just this part: " sqrt(x^2-a^2)" with that minus sign there. yours has a +

Answer 10

try use u =sqrt(4.x+1)

Answer 11

sorry it should be a + sign

Answer 12

raphael, then where is my du in the integral?

Answer 13

partial fractions again

Answer 14

no its wrong

Answer 15

I was trying to get tan(theta) and sec^2(theta) in my integral so I could use u substitution, but I got sec/tan^3