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Integral test for the Casio Fx-CG500
09-01-2017, 09:56 PM
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RE: Integral test for the Casio Fx-CG500
(09-01-2017 08:12 PM)Namir Wrote:  I found an interesting set of integrals in the book "Inside Interesting Integrals" by Paul J. Najin. The author shows a set of integral in the preface section:

int(cos(x)*sin(4*x)/x,x,0,infinity)
int(cos(x)*cos(x/2)*sin(4*x)/x,x,0,infinity)
int(cos(x)*cos(x/2)*cos(x/3)*sin(4*x)/x,x,0,infinity)

and so an. Interestingly, each of the above integrals evaluates to pi/2. I tried to evaluate the integral int(cos(x)*cos(x/2)*sin(4*x)/x,x,0,infinity) (I am writing it using HP Prime form) with the Casio fx-CG500, but the calculator just kept on computing! I tried the same integral with the HP Prime which promptly returned a pretty version on the integral. Subtle AND polite!

I then tried int(cos(x)*cos(x/2)*sin(4*x)/x,x,0,1000*pi) on the HP Prime and instantly obtained 1.57061752887. I tried the same with the Casio ... which kept on calculating!!! It took the DM-15L just about 2 minutes to match the result of the HP Prime.

I am disappointed with the Casio fx-CG500. Good job HP ... at least for the approximation of the integral's limit.

Namir
These integrals also lock up my TI Nspire CX CAS. Well, there is a key combination to interrupt the calculation, but it seems to automatically restart the calculation afterwards. I had to use the reset button on the back!
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RE: Integral test for the Casio Fx-CG500 - ijabbott - 09-01-2017 09:56 PM



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