tylrw
幼苗
共回答了14个问题采纳率:78.6% 举报
1/2(√2+√3)-3/4(√2-√27)
=1/2(√2+√3)-3/4(√2-3√3)
=√2/2+√3/2-3√2/4+9√3/4
=√2/2-3√2/4+√3/2+9√3/4
=-√2/4+11√3/4
=11√3/4-√2/4
x=√3+1,y=√3-1
(1)x²+2xy+y²
=(x+y)²
=(√3+1+√3-1)²
=(2√3)²
=12
(2)x²-y²
=(x+y)(x-y)
=[(√3+1)+(√3-1)][(√3+1)-(√3-1)]
=2√3*2
=4√3
1年前
9