解由x属于区间[π/8,3π/4]
即π/8≤x≤3π/4
即π/4≤2x≤3π/2
即0≤2x-π/4≤5π/4
即2x-π/4=π/2时,即x=3π/8时,y有最大值y=√2×1=√2
2x-π/4=5π/4时,即x=3π/4时,y有最小值y=√2×(-√2/2)=-1
解由x属于区间[π/8,3π/4]
即π/8≤x≤3π/4
即π/4≤2x≤3π/2
即0≤2x-π/4≤5π/4
即2x-π/4=π/2时,即x=3π/8时,y有最大值y=√2×1=√2
2x-π/4=5π/4时,即x=3π/4时,y有最小值y=√2×(-√2/2)=-1