y=-sin2x单调区间
先求sin2x的单调区间
y=-sin2x单调区间
2x∈(-π/2+2kπ,π/2+2kπ)单调减
2x∈(π/2+2kπ,3π/2+2kπ)单调增
x∈(-π/4+kπ,π/4+kπ)单调减
x∈(π/4+kπ,3π/4+kπ)单调增
y=-sin2x单调区间
先求sin2x的单调区间
y=-sin2x单调区间
2x∈(-π/2+2kπ,π/2+2kπ)单调减
2x∈(π/2+2kπ,3π/2+2kπ)单调增
x∈(-π/4+kπ,π/4+kπ)单调减
x∈(π/4+kπ,3π/4+kπ)单调增