来自潘剑锋的问题
高一数学题ax3=by3=cz3,且1/x+1/y+1/z=1求证:(ax2+by2+cz2)^(1/3)=a^(1/3)+b^(1/3)+c^(1/3)
高一数学题
ax3=by3=cz3,且1/x+1/y+1/z=1求证:(ax2+by2+cz2)^(1/3)=a^(1/3)+b^(1/3)+c^(1/3)
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2020-01-26 07:01
高一数学题ax3=by3=cz3,且1/x+1/y+1/z=1求证:(ax2+by2+cz2)^(1/3)=a^(1/3)+b^(1/3)+c^(1/3)
高一数学题
ax3=by3=cz3,且1/x+1/y+1/z=1求证:(ax2+by2+cz2)^(1/3)=a^(1/3)+b^(1/3)+c^(1/3)
设ax^3=by^3=cz^3=k∴ax^2=k/x,by^2=k/y,cz^2=k/za^(1/3)x=b^(1/3)y=a^(1/3)z=k^(1/3)∴原式左边=(ax^2+by^2+cz^2)^(1/3)=(k/x+k/y+k/z)^(1/3)=(k*1)^(1/3)=k^(1/3)原始右边=a^(1/3)+b^(1/3)+c^(1/3)=k^(1/3)/x+k^...