Most of the people I see gets confused about this rule. This rule actually cannot determine the number of roots. Specifically, this rule determines the NUMBER OF MAXIMUM real positive or negative roots by checking the number of change of signs in f(x) and f(-x). The word MAXIMUM should be given emphasis.

For the people who don't know this rule: Check this link
http://en.wikipedia.org/wiki/Descartes'*rule*of_signs

## Comments

Sort by:

TopNewestCan you contribute to the wiki on Descartes Rule of Sign here on Brilliant ?

Thanks :) – Azhaghu Roopesh M · 2 years ago

Log in to reply

– Saswata Dasgupta · 2 years ago

Sure, but can you tell me how can I contribute?Log in to reply

Just got to the link that I have provided, click on "edit this page" and add the content that you think is appropriate :) – Azhaghu Roopesh M · 2 years ago

Log in to reply

I think this rule also tells us about the complex roots. – Trishit Chandra · 2 years ago

Log in to reply

– Saswata Dasgupta · 2 years ago

Obviously you can get the MAXIMUM number of complex roots by taking out the number of MAXIMUM real roots from the total rootsLog in to reply

– Trishit Chandra · 2 years ago

Yes I've checked the wolfram. It also says this.Log in to reply