Find the volume of the solid generated by revolving the area.

bob29
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Homework Statement


Find the volume of the solid generated by revolving the area bounded by
y = sec[x], y= \sqrt{2}
- \pi/4 \leq x \leq \pi/4 about the x-axis

Or
[PLAIN]http://img838.imageshack.us/img838/1552/mathprobq6.jpg

Homework Equations


a = lower limit = --\pi/4
b = upper limit = \pi/4
V = \int a->b R2 - r2 dx

The Attempt at a Solution


V = \int a->b R2 - r2 dx
V = \pi \sqrt{2}2 - \pi*sec[x] = a->b(\pi*2x) - (\pi*[tan[x]])a->b

Note: Ans = \pi[\pi - 2]
 
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bob29 said:

Homework Statement


Find the volume of the solid generated by revolving the area bounded by
y = sec[x], y= \sqrt{2}
- \pi/4 \leq x \leq \pi/4 about the x-axis

Or
[PLAIN]http://img838.imageshack.us/img838/1552/mathprobq6.jpg


Homework Equations


a = lower limit = --\pi/4
b = upper limit = \pi/4
V = \int a->b R2 - r2 dx


The Attempt at a Solution


V = \int a->b R2 - r2 dx
V = \pi \sqrt{2}2 - \pi*sec[x] = a->b(\pi*2x) - (\pi*[tan[x]])a->b

Note: Ans = \pi[\pi - 2]
What's your question? You have the integral set up correctly (but horribly formatted). The only things missing are the limits of integration.

Here's your integral, formatted a little more nicely. Click the integral to see what I did.
V = \pi \int_a^b \left( 2 - sec^2(x) \right)dx
 
Last edited by a moderator:
Thanks anyway, yep not familiar with the formatting.
But problem is solved.
 
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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