sin7度+cos15度*sin8度/cos7度-sin15度*sin8度=?
问题描述：
sin7度+cos15度*sin8度/cos7度-sin15度*sin8度=?
答
(sin7+cos15sin8)/(cos7-sin15sin8) =[sin7+cos(7+8)sin8]/[cos7-sin(7+8)sin8] =[sin7+(cos7cos8-sin7sin8)sin8]/[cos7-(sin7cos8+sin8cos7)sin8] =(sin7+cos7cos8sin8-sin7sin²8)/(cos7-sin7sin8cos8-sin&sup...