Wrong result from calculation

Dear all,
I have a question about high precision calculation of the fraction 1/998001 in Matlab. I use
vpa(1/998001,200)
which produces the following result
0.000001002003004005005955287066314596255978131011943332850933074951171875
On the Numberphile channel on youtube, they prove that the result should be
0.000001002003004005006007 .. 996997999
which has higher precision than the obtain result in MATLAB and it appears that there is some numerical error. Do you have any idea why is that?
Thank you
Regards,
Veselin

回答(1 个)

By the time you call vpa, MATLAB has already performed the division in double precision. So you're displaying the double precision value that results from that division to 200 decimal places.
Perform the division symbolically.
x1 = vpa(1/998001, 200)
x2 = vpa(sym(1)/998001, 200)

2 个评论

“Power of symbolic toolbox” never lets down ;)
Thank you very much!

请先登录,再进行评论。

类别

帮助中心File Exchange 中查找有关 Logical 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by