matlab,根据y与k的关系，求系数a,b,c,必采纳，急，必采纳 看懂必采纳
\u9009A\u8fd8\u662fB\u8fd8\u662fC,\u5fc5\u91c7\u7eb3\u3001\u60ac\u8d4f\uff0c\u5f88\u6025\u7684\uff01\u5feb\u5feb\u5febb
\u5148\u628a\u5206\u5b50\u5206\u6bcd\u5012\u8fc7\u6765\u7136\u540e\u4ee4(a-b)/x=\uff08b-c\uff09/y=(c-a)/z =K X=(a-b)/K,Y=\uff08b-c\uff09/K,Z=(c-a)/K \u6240\u4ee5,x+y+z=(A-B+B-C+C+A)/K=0
参考代码：
k=[0 47 93 140 186 279 372 465 558 651];
y=[18.98 27.35 34.86 38.52 38.44 37.73 38.43 43.87 42.77 46.22];
f=@ (x,k)x(1)*(1-x(2)*exp(-x(3)*k));
x=lsqcurvefit(f,[45 1 0.01],k,y)
plot(k,y,'o',k,f(x,k),'r.-')
xlabel 施肥量K（kg/ha）, ylabel 产量（t/ha）
legend('原始数据','拟合曲线')
运用回归分析算法来做，可以用spss，也可以用matlab来做
matlab中的polyfit函数用于曲线拟合。polyfit(k,y,2)
就按照题目说的穷举呗
a为18.98b为-0.7c为0.01
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