作业帮500²—1000x498+498²已知X+Y=1/2,XY=1/8,求X²+Y²的值
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500²—1000x498+498²已知X+Y=1/2,XY=1/8,求X²+Y²的值
500²—1000x498+498²
已知X+Y=1/2,XY=1/8,求X²+Y²的值
500²—1000x498+498²已知X+Y=1/2,XY=1/8,求X²+Y²的值
500²—1000x498+498²=500²—2×500x498+498²=(500-498)²=2²=4
X²+Y²=X²+Y²+2XY-2XY=(X+Y)²-2XY=(1/2)²-2×1/8=1/4-1/4=0
5002—1000x498+4982=（500+498)2
X2+Y2=（X+Y)2-2XY=0
500²—1000x498+498²
=(500-498)^2
=2^2
=4
x^2+y^2
=(x+y)^2-2xy
=(1/2)^2-2*(1/8)
=1/4-1/4
=0
是：500²—1000x498+498²=500²—2×500x498+498²=(500-498)²=2²=4
X²+Y²=X²+Y²+2XY-2XY=(X+Y)²-2XY=(1/2)²-2×1/8=1/4-1/4=0
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x²+y²=0
x²+y²=（x+y)²-2xy
5002-1000×498+4982
=5002-2×500×498+4982
=（500-498）2
=22
=4
x2+y2
=x2+2xy+y2-2xy
=(x+y)2-2xy
=(1/2)2-2×(1/8)
=1/4-1/4
0
500²-1000x498+498²
=500²-2×500x498+498²
=(500-498)²=2²=4
X²+Y²=(X+Y)²-2XY
=1/4-1/4
=0
5002-1000×498+4982
=5002-2×500×498+4982
=（500-498）2
=22
=4
x2+y2
=x2+2xy+y2-2xy
=(x+y)2-2xy
=1/4-1/4
0