Is the solution for trig substitution correct?

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Homework Statement


I(1/(9x^2+6x-8)^(1/2),x)
I( 1/( (3x+1)^2-9 )^(1/2),x )
3x+1=3secT
dx=secTtanTdT
I( (secTtanT)/3tanT,T )
(1/3)I( secT,T)
(1/3)|secT+tanT|+C
secT=(3x+1)/3
tanT=(9x^2+6x-8)^(1/2)/3
solution: (1/3)|(3x+1)/3+(9x^2+6x-8)^(1/2)/3|
my book is showing :(1/3)|(3x+1)+(9x^2+6x-8)^(1/2)|


Homework Equations





The Attempt at a Solution

 
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nameVoid said:

Homework Statement


I(1/(9x^2+6x-8)^(1/2),x)
I( 1/( (3x+1)^2-9 )^(1/2),x )
3x+1=3secT
dx=secTtanTdT
I( (secTtanT)/3tanT,T )
(1/3)I( secT,T)
(1/3)|secT+tanT|+C
secT=(3x+1)/3
tanT=(9x^2+6x-8)^(1/2)/3
solution: (1/3)|(3x+1)/3+(9x^2+6x-8)^(1/2)/3|
my book is showing :(1/3)|(3x+1)+(9x^2+6x-8)^(1/2)|

Double-check these steps.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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