2016年4月15日 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

2015年4月20日 · Using this formula to decompose $\cos z = i$ into real and imaginary parts gives the (equivalent) ...

2017年8月2日 · $\begingroup$ $\cos z=2$ iff $\cosh iz=2$. $\endgroup$ – Angina Seng. Commented Aug 2, 2017 at 11:46

2017年9月15日 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

2016年12月3日 · I am trying to prove that $ \overline {\cos(z)} = \cos(\bar z)$ I have tried this myself but I can't see where I have gone wrong. I'd like to continue to try to prove it using the method I will specify and not the double angle formulas.

2015年5月5日 · The idea is to apply the same technique used in one of the answers of this problem Maximum of $|\sin(z)|$ as $\{z: |z| \leq 1 \} $ Use the identity: $$\vert\cos z\vert^2=\vert \cos (x+iy)\vert^2=\cos^2 x + \sinh ^2 y$$. What is left is just to find the maximum of $\cos x$ and the maximum of $\sinh y$ in the boundary.

Solving $\cos A + \cos B + \cos C = 0$ and $\sin A + \sin B + \sin C = 0$ using complex numbers Hot Network Questions Building an 8080 based computer

2019年5月12日 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

2020年6月19日 · Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.