π/6 sinα=1/2,cosα=√3/2,tαnα=√3/3 cotα=√3
π/4 sinα=√2/2,cosα=√2/2,tαnα=1 cotα=1
π/3 sinα=√3/2,cosα=1/2,tαnα=√3 cotα=√3/3
π/2 sinα=1,cosα=0,tαnα不存在,cotα=0