(1)00.故依均值不等式得:y=3x-2x^2=(1/2)·2x·(3-2x)≤(1/2)[(2x+3-2x)/2]^2=9/8.∴2x=3-2x,即x=3/4时,所求最大值为:9/8.(2)x>-1,则x+1>0,∴x+1/(x+1)+3=(x+1)+1(x+1)+2≥2√[(x+1)·1/(x+1)]+2=4.∴x+1=1/(x+1),即x=0时,所求最大值为:log(4)=-2.
设x=sint用三角代换即可