Hi, I wonder if there is a typo in the sentence just before the formula (11.2.5): “However, by convexity the function values on the entire line λx+(1−λ)x have to be less than f(x’)”, instead of “less than f(x’)”, shouldn’t it be “less than f(x)” here? Thanks a lot!

Hi @nxby, i believe you are right! Could you make a PR and be a contributor? https://d2l.ai/chapter_appendix-tools-for-deep-learning/contributing.html

Hi, Does anyone have solution of Convexity exercises which is in this book?

I think the final line in Eq.(11.2.15) should be:

f(λx+(1−λ)y) = … = λf(x)+(1−λ)f(y)

λf(x)+(1−λ)g(y) is a typo