1.T=2π/3
2.A=4 f(π/12)=4*sin(π/4+φ)=4
π/4+φ=2kπ+π/2 k为整数
因为0<0<φ<π φ=π/4
f(2/3*a+π/12)=4sin(3*(2/3*a+π/12)+π/4)=4sin(2a+π/2)=4cos2a=12/5
cos2a=3/5
1.T=2π/3
2.A=4 f(π/12)=4*sin(π/4+φ)=4
π/4+φ=2kπ+π/2 k为整数
因为0<0<φ<π φ=π/4
f(2/3*a+π/12)=4sin(3*(2/3*a+π/12)+π/4)=4sin(2a+π/2)=4cos2a=12/5
cos2a=3/5