(Sin7°+cos15°sin8°)÷(cos7°－sin15°sin8°)=?(sin7+cos15sin8)/(cos7-sin15sin8) 积化和差 =[sin7+(sin23-sin7)*0.5]/[cos7+(cos23-cos7)*0.5] =(0.5sin7+0.5cos23)/(0.5cos7+0.5cos23) 约分,和差化积 =(sin15*sin8)/(cos15*cos8) 约分 =tan15 半

(Sin7°+cos15°sin8°)÷(cos7°－sin15°sin8°)=?(sin7+cos15sin8)/(cos7-sin15sin8) 积化和差 =[sin7+(sin23-sin7)*0.5]/[cos7+(cos23-cos7)*0.5] =(0.5sin7+0.5cos23)/(0.5cos7+0.5cos23) 约分,和差化积 =(sin15*sin8)/(cos15*cos8) 约分 =tan15 半
(Sin7°+cos15°sin8°)÷(cos7°－sin15°sin8°)=?
(sin7+cos15sin8)/(cos7-sin15sin8) 积化和差
=[sin7+(sin23-sin7)*0.5]/[cos7+(cos23-cos7)*0.5]
=(0.5sin7+0.5cos23)/(0.5cos7+0.5cos23) 约分,和差化积
=(sin15*sin8)/(cos15*cos8) 约分
=tan15 半角公式
=(1-cos30)/sin30
=2-3^(1/2) 就是2-根号3
(我咋算到最后是tan5tan8.而且此解中步骤好像也有问题)
到底咋作啊!

(Sin7°+cos15°sin8°)÷(cos7°－sin15°sin8°)=?(sin7+cos15sin8)/(cos7-sin15sin8) 积化和差 =[sin7+(sin23-sin7)*0.5]/[cos7+(cos23-cos7)*0.5] =(0.5sin7+0.5cos23)/(0.5cos7+0.5cos23) 约分,和差化积 =(sin15*sin8)/(cos15*cos8) 约分 =tan15 半
=(sin(15-8)+cos15sin8)/(cos(15-8)-sin15sin8=(sin15cos8-cos15sin8+cos15sin8)/(cos15sin8+sin15cos8-sin15sin8)=sin15/cos15=tan15=tan(45-30)=2-根3