f(x)=3sin(2x+π/4)单增:2x+π/4∈[2kπ-π/2,2kπ+π/2]x∈[kπ-3π/8,kπ+π/8]k∈z所以单调增区间为[kπ-3π/8,kπ+π/8]k∈z单调减区间为单调增区间向右平移π/2个单位为[kπ+π/8,kπ+5π/8]k∈z最小正周期为2π/2=π
