已知(x+y)^2=7,(x-y)^2=3,求(1)x^2=y^2 (2)x^4=y^4的值 (3)x^6=y^6
问题描述:
已知(x+y)^2=7,(x-y)^2=3,求(1)x^2=y^2 (2)x^4=y^4的值 (3)x^6=y^6
答
已知(x+y)^2=7,(x-y)^2=3,求(1) x^2+y^2 (2)x^4+y^4的值 (3)x^6+y^6题目都打错了你两式相加除以2的x^2+y^2=5,两式相减法除以2的xy=1x^2+y^2=5两边平方得x^4+y^4+2xyxy=25 ,x^4+y^4=23(x^2+y^2)(x^4+y^4)=2...