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Companion webpage to the book "Mathematics For Machine Learning"
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Possible typo in question 7.1 #281

Closed Sand-Deep closed 5 years ago

Sand-Deep commented 5 years ago

You may have intended this but question 7.1 asks the reader to find the stationary points of a function that does not have any stationary points. Is there a sign error somewhere?

I have plotted the function question_7.1.pdf

Sand-Deep commented 5 years ago

Also, a slightly pedantic point related to the phrasing in this question. I think a saddle point is only possible where there is more than 1 independent variable, so that you get a min in one direction and a max in another, whereas the function in the question is univariate.

mpd37 commented 5 years ago

Saddle points also exist in 1D. Example: f(x) = x^3 https://en.wikipedia.org/wiki/Saddle_point

Sand-Deep commented 5 years ago

I see, thanks for pointing that out.

I guess I didn't think of x^3 looking much like a saddle in my mind.