y=1/2*cos(πx+π/3)-sin[π-(πx+5π/6)]
=1/2*cos(πx+π/3)-sin(-πx+π/6)
=1/2*cos(πx+π/3)-cos[π/2-(-πx+π/6)]
=1/2*cos(πx+π/3)-cos(πx+π/3)
=-1/2*cos(πx+π/3)
y递减则cos递增
cosx增区间是(2kπ-π,2kπ)
2kπ-π
y=1/2*cos(πx+π/3)-sin[π-(πx+5π/6)]
=1/2*cos(πx+π/3)-sin(-πx+π/6)
=1/2*cos(πx+π/3)-cos[π/2-(-πx+π/6)]
=1/2*cos(πx+π/3)-cos(πx+π/3)
=-1/2*cos(πx+π/3)
y递减则cos递增
cosx增区间是(2kπ-π,2kπ)
2kπ-π