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Evaluate this integral:

∫ (4y dy) / √(2y^2 + 1)

2007-11-30 03:44:21 · 2 answers · asked by NEEDs MATH HELP!! 1 in Science & Mathematics Mathematics

2 answers

Just use a simple substitution:

let u = (2y^2+1)

then du = 4y dy (quite convinient)

now just substitute back:

∫ du / √(u)

∫ u^(-1/2) du

u^(1/2) / (1/2)

2 u ^ (1/2)

now just replace u

2 (2y^2+1)^(1/2)

2 * √(2y^2+1)

2007-11-30 03:53:19 · answer #1 · answered by grompfet 5 · 1 0

I take it you really meant INT 4y /√(2y^2 + 1) dy – at least I hope you did!
The way I look at it is this:
if v = (2y^2 + 1)^ 0.5
then v’ = -0.5 (2y^2 + 1)^ -0.5 x 4y ( which is nearly the same as the question)
So ….
PS I would love to know how you get integral sign - I just got a box when I tried

2007-11-30 12:19:26 · answer #2 · answered by Anonymous · 0 0

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