2 replies to this topic

[Dwardom]

Hello everybody,
I've got my AP exam coming up, and for the longest time, I've depended on an old TI-84 to do my integration in polar mode.
I've decided to finally seek help. Can anyone shed light onto this for me? Thanks ;D

Example: Suppose I wanted to find the area inside the inner loop of r=1+2cos(theta)
Using the x-calc feature, I find my limits of integration to be 2.09439 and 4.18879. I then go to the Run-Matrix feature and press MATH, -->, Integral dx. Where do I go to integrate d(theta)

[saad]

I have Casio prism, so I will try to help you. So here is what I did: First, this is for the prizm, so it might not be the same for you. I put my prizm into radien mode, and then I went to calc->function then solveN function. I entered your equation (1+2cosx). The solveN function is basically solveX by setting the equation equal to zero automatically in that case (r=0). Of course, I had many solutions for x values which are actually theta angles. given by the calc, since it is a loop. Then, I looked at solutions that's in the range of 0 to 2pi (which is only x values of 2pi/3,4pi/3, you could also do it by hand by solving arcos(-0.5) which is (n)2pi/3, where n is an integer and its values fall between 0 to 2pi [n=1,2 anything larger will be more than 2pi]). I pressed calc then the integral symbol, then your 2.x values will be lower limit and upper limit . I Googled how to integrate a loop and found out that it is (0.5) (1+2cosx)^2 dx. I typed it into my calculator and noticed that you don't need to have it in terms of theta because Casio can't do that except in terms x (you shouldn't worry because x=theta here). I got 0.5435164422. I hope you find this helpful.

(edited for grammar by mod)

Edited by Forty-Two, 19 April 2012 - 08:39 PM.

[flyingfisch]

Hi Dwardom and saad, welcome to UCF!

If you have not already done so, you guys should introduce yourselves here : http://www.casiocalc...?showtopic=5677

Hello everybody,
I've got my AP exam coming up, and for the longest time, I've depended on an old TI-84 to do my integration in polar mode.
I've decided to finally seek help. Can anyone shed light onto this for me? Thanks ;D

Example: Suppose I wanted to find the area inside the inner loop of r=1+2cos(theta)
Using the x-calc feature, I find my limits of integration to be 2.09439 and 4.18879. I then go to the Run-Matrix feature and press MATH, -->, Integral dx. Where do I go to integrate d(theta)

If you could tell us what calculator you owned, we might be able to help more.