complex analysis - How to prove Euler's formula: $e^{it}=\cos t +i\sin t$? - Mathematics Sta
Could you provide a proof of Euler's formula: $e^{it}=\cos t +i\sin t$ ? thanks. ... Assuming you mean $e^{ix}=\cos x+i\sin x$, one way is to use the MacLaurin series for sine and cosine, which are known to converge for all real $x$ in a f...