已知x+2y+3z=1,求求u=x²/(x+1)+4y²/(2y+1)+9z²/(3z+1)最小值根据柯西不等式,[x²/(x+1)+4y²/(2y+1)+9z²/(3z+1)]·[(x+1)+(2y+1)+(3z+1)]≥(x+2y+3z)²∴[x²/(x+1)+4y²/(...