- #1

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**[SOLVED] volumes... last week of calc**

i was absent when we went over the volume section.

y= 1/x, x= 1, x= 2, y= 0,; about the x-axis

[tex]

\int^{1}_{2} \pi \frac{1}{x} dx

[/tex]

i don't know whats next. can anyone inform me, please

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- Thread starter physicsed
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- #1

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i was absent when we went over the volume section.

y= 1/x, x= 1, x= 2, y= 0,; about the x-axis

[tex]

\int^{1}_{2} \pi \frac{1}{x} dx

[/tex]

i don't know whats next. can anyone inform me, please

- #2

Dick

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- #3

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if you help me with this problem, i am sure i will get the rest of the problems.

- #4

Dick

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It's a power law integral. Like x^n. What's n in this case? What's the antiderivative?

- #5

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[tex] \pi \int^{2}_{1} \frac{1}{x^2} dx[/tex]

Last edited:

- #6

Dick

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Fine start. Now what's the antiderivative of 1/x^2?

- #7

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[tex] \pi [ \frac{x^{-3}}{-3}] [/tex]

- #8

Dick

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Beep. Wrong. The antiderivative of x^n is x^(n+1)/(n+1). What's n in this case? Unless that's a careless error because you are paying more attention to texing than thinking, you may have missed more than 'volumes'.

Last edited:

- #9

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since it's divided by 1, isn't it negative n

=x^-2

=x^-2

- #10

Dick

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Yes, it is. Can you fix your antiderivative?

- #11

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(-1/3)x^-3

- #12

Dick

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Beep. Beep. Beep. You goofed it again. What's -2+1? Think this time.

- #13

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righttt

pi [(1/-1)x^-1]

pi [(1/-1)x^-1]

- #14

Dick

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righttt

pi [(1/-1)x^-1]

Much better! You've got it now, right? And you promised that meant you could get all the others.

- #15

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thanks buddy

your awesome

your awesome

- #16

Dick

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It's "you're awesome". I'm correcting grammar tonight. Thanks.

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