Skip to main content

Questions tagged [inverse-trigonometric-functions]

Filter by
Sorted by
Tagged with
2 votes
2 answers
178 views

Is there a closed formula for this sum? [duplicate]

The sum is $$f_{n}=\sum_{k=1}^{n}\arctan\left(\frac{1}{\sqrt{k}}\right)$$ I figured I need a closed formula for this or for the cosine of this whole expression in order to get a polar representation ...
עמית חי לרמן's user avatar
1 vote
3 answers
237 views

Trying to find an identity for $\arctan(ab)$ in terms of any other trigonometric function

I am trying to find an identity for $\arctan(ab)$ in terms of any trigonometric function involving $a$ and $b$ being separate. I have attempted doing so using $(\arctan(a)+\arctan(b))^2$ but that got ...
Yajat Shamji's user avatar