f(x)、1 斜渐近线 4 再计算 [(x)-kx] s=1/4*x’;s1 b(y, s simplify(s1) ans=-1/4*(5*x-9)/(x-1) b 4 有斜渐近线 我们把找到的特殊点,渐近线先画出来 c1f,x=-3:1/20:6; y1=1/4*x-5/4 plot(x, y1, ' k'), hold on plot(-1,-2,’r.,3,0,’r.’,0,-9/4’r.), hold on p1ot([1,1],[2.8,2.8],k,[0,0],[2.8,2.8],"b’,[-3,6],[0,0],’b axis([-4,6,-3,3])斜渐近线: = k 再计算 s='1/4*x';s1=symsub(y,s); simplify(s1) ans = -1/4*(5*x-9)/(x-1) 有斜渐近线 我们把找到的特殊点, 渐近线先画出来 clf,x=-3:1/20:6; y1=1/4*x-5/4; plot(x,y1,'k'),hold on plot(-1,-2,'r.',3,0,'r.',0,-9/4,'r.'),hold on plot([1,1],[-2.8,2.8],'k',[0,0],[-2.8,2.8],'b',[-3,6],[0,0],'b') axis([-4,6,-3,3])