Question

已知X=A分之B+C,Y=B分之C+A,Z=C分之A+B,求X分之1+X + Y分之1+Y + Z分之1+Z的值

Answer 1

解 1+X=(A+B+C)/B+C 1+Y=(A+B+C)/A+C 1+Z=(A+B+C)/A+B

X/(1+X)= A/(A+B+C) Y/(1+Y)=B/(A+B+C) Z/(1+Z)=C/(A+B+C)

故 X/1+X+Y/1+Y+Z/1+Z=A/(A+B+C)+B/(A+B+C)+C/(A+B+C)=（A+B+C）/(A+B+C) =1