问题描述: 计算1sin50°+3cos50° 1个回答 分类:数学 2014-09-19 问题解答: 我来补答 1sin50°+3cos50°=cos50°+3sin50°sin50°cos50°=2(12cos50°+ 32sin50°)sin50°cos50°=2(sin30°cos50°+ cos30°sin50°)sin50°cos50°=2sin(30°+50°)sin50°cos50°=2sin80°sin50°cos50°=2sin80°12sin100°=2sin80°12sin80°=4故答案为4 展开全文阅读