This question was asked in Example 24
cos(x y)=cosx.cosy-sinx. Siny prove geometrically

ಸುಮಂತ್ ಟಿ ಸಿ's image
ಸುಮಂತ್ ಟಿ ಸಿ
Jan. 31, 2018, 7:29 p.m.