log3x+log3y=2log3(x-2y),求log2x/y的值 已知2x+3y+6z不等于1,求证1/x + 1/y=1/z
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log3x+log3y=2log3(x-2y),求log2x/y的值 已知2x+3y+6z不等于1,求证1/x + 1/y=1/z
log3x+log3y=2log3(x-2y),求log2x/y的值 已知2x+3y+6z不等于1,求证1/x + 1/y=1/z
log3x+log3y=2log3(x-2y),求log2x/y的值 已知2x+3y+6z不等于1,求证1/x + 1/y=1/z
(1) x>0,y>0
log3x+log3y=2log3(x-2y),
log3(xy)=log3(x-2y)²
xy=(x-2y)²
x²-5xy+4y²=0
(x-4y)(x-y)=0
x=4y 或x=y
若x=y,则x-2y
log3x+log3y=2log3(x-2y),
xy=(x-2y)²
xy=x²-4xy+4y²
x²-5xy+4y²=0
(x-4y)(x-y)=0
x=4y或x=y
x=y是,同时出现2log3(x-2y)=2log3(-y),和log3y,必有一项不对,
所以x=y舍去。
x=...
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log3x+log3y=2log3(x-2y),
xy=(x-2y)²
xy=x²-4xy+4y²
x²-5xy+4y²=0
(x-4y)(x-y)=0
x=4y或x=y
x=y是,同时出现2log3(x-2y)=2log3(-y),和log3y,必有一项不对,
所以x=y舍去。
x=4y
log2x/y=log(2)4=2
已知2x+3y+6z不等于1,求证1/x + 1/y=1/z
这个题和上题有关系吗?缺条件啊。
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log3x+log3y=2log3(x-2y),
log3(x*y)=log3(x-2y)^2
xy=(x-2y)^2
(x-y)(x-4y)=0
x=y(舍去) 或x=4y
log(3)x/y=log(3)4