Solving an Intriguing Integral: x-1 in the First Quadrant

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Homework Statement


\int\int_R x-1 dA
R is the region in the first quadrant enclosed between y=x and y=x^3



Homework Equations





The Attempt at a Solution



I set up the bounds as follows: \int_{x=0}^1\int_{y=x^3}^x x-1 dydx

Integrating, I get -7/60, verified with CAS.

I thought this was an easy problem but my answer doesn't match the textbook (-1/2 but could be a misprint, right?) or did I somehow put the bounds of integration wrong?
 
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It looks fine to me.
 
I agree with your answer
 
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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