a-b=1/2=>两边平方得a^2+ b^2 -2ab = 1/4所以2ab = 3/4ab = 3/8a^2b^2 = 9/16(a+b)^4=((a+b)^2)^2=(a^2 + b^2 + 2ab)^2=(1 + 3/4)^2=49/16
a²+b²=1a-b=1/2 (a-b)²=1/4 a²-2ab+b²=1/4 ab=3/8a²b²=(ab)²=9/64(a+b)^4=(a²+2ab+b²)²=(1+3/4)²=49/16