In addition: y = sin (x+70-60)+cos (x+70-30).
= sin(x+70)/2-√3c OS(x+70)/2+√3c OS(x+70)/2+sin(x+70)/2
=sin(x+70)
2、T=8-2=6，ω=π/3
f(x)=Asin(πx/3+φ)
X=3 is the symmetry axis, and f(3)=Asin(π+φ)=A, so φ=-π/2.
f(x)=Asin(πx/3-π/2)
πx/3-π∈[2kπ-π/2，2kπ+π/2]
The solution is [6k+3/2, 6k+9/2], k ∈ z.