Question

数学帝进来帮小弟一个忙已知(1+sinx)/cosx=-1/2 则cosx/(sinx-1)的值多少啊 先谢过大家了还有

Answer 1

第二题

∵tan α=(sin α)/(cos α)

又∵tan α=cos α

∴tan α=(sin α)/(cos α)=cos α

sin α=(cos α)*(cos α)

∵(sin α)*(sin α)+(cos α)*(cos α)=1

∴(sin α)*(sin α)+(cos α)*(cos α)=(sin α)*(sin α)+sin α=1

解得：sin α=（-1±根号5）/2

∵|sin α|≤1,且sin α=(cos α)*(cos α)

∴sin α=（-1+根号5）/2