Sunday, December 6, 2009

post sixteen

This week was one more week closer to mid terms. This week we learned several things.

Some of the things that we learned were intergration of washers and disk.

The formula for the volume of disks is S (top)^2 - (bottom)^2 dx

The formula for the area of washers is S (top) - (bottom)

The steps are:
1. Draw the graphs of the equations
2. Subtract top graph's equation by the bottom graph's equation(in disks each equation would be squared)
3. Set equations equal and solve for x to find bounds
4. Plug in the bounds and the outcome of step 2
5. Integrate

These steps are fairly simple but you must remember to draw the graphs.

One thing that i am not catching on to is intergration of trig functions. Like i know the formulas but cant work a problem.

2 comments:

  1. for the one's with trig functions..if you know the formulas then you're half way there...
    like if it's .. to intergrate -sin(x+2)then you know that the derivative of cos is -sin so then you just put -sin(x+2)
    it's defidently tricky because now we're working backwards..but i hope this helps!

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  2. okay, so i know you know how to take the derivative of a trig function. you knew it better than i did at one point. taking the integral is the exact opposite, with negatives and positives and everything

    so, derivative of cos = -sin
    so, integral of cos = cos

    derivative of sin = cos
    integral of sin = -sin

    same with all the others too..
    at least i think i'm right.. ha

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