The tuning theorem of high school mathematics is a difficult topic.
1 Because A and B are acute angles, COSA >: 0, cosB & gt0 cosA= radical sign (1-Sina 2) = 2 times radical sign 5/5, CosB= radical sign (1-sinb 2) = triple radical sign/kloc-0. 50= radical number 50/ 10A+B=arcsin (radical number 50/ 10)2, which is composed of a/sina = b/sinb = c/sinca/b = sina/sinb = (radical number 5/5)/ (radical number 6544)