Summation Notation for TI86Date: 10/29/2001 at 21:59:46 From: Nicole Colt Subject: Summation notation for TI86 Dear Dr. Math, I am currently taking Calculus 1 from the community college in town. We were talking about summation notation and I was wondering if there was an easier way to do our assignment on a TI86. We are allowed to use a program called MatLab, but I am usually unable to get the lab over before it closes down. An example problem is: 20 sigma (2^k)/k k=1 Thank you for your help, Nicole Colt Date: 10/29/2001 at 23:20:02 From: Doctor Paul Subject: Re: Summation notation for TI86 What you want to do is create a sequence and then sum the sequence. Both menu items are contained under the "List > OPS" (2nd + subtraction key, then F5) category. For example if you wanted to compute: 4 sigma k^2 k = 1 You would do: seq(x^2,x,1,4) [you can't use k as the variable - it will cause a syntax error] and the Calculator would return the list: {1 4 9 16} Then to sum the values: sum Ans and the calculator gives the answer: 30. Or you could do it all in one step: sum seq(x^2,x,1,4) and you get 30. So for your problem you would do: sum seq( 2^x/x,x,1,20) The answer is: 111142.374448 = 1617069867008/14549535 [The calculator wouldn't tell me how to write the given number as a rational number - I used a different computer program to do that.] I hope this helps. Write back if you'd like to ask some more questions about it. - Doctor Paul, The Math Forum http://mathforum.org/dr.math/ |
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