拟合出各点的曲线后,用polyder函数求其导数,以在曲线上画出切线。但不知为什么画出的切线没有在曲线上,而且还不对。请大侠们赐教,谢谢!程序及图如下:
y=log10(i);coff=polyfit(t,y,2);plot(t,y,'*');hold onval=polyval(coff,t);%曲线拟合plot(t,val,'k','linewidth',2);hold onder=polyder(coff);val1=polyval(der,t);%切线拟合plot(t,val1,'k','linewidth',2);hold on
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