from numpy import linspace,log from matplotlib.pyplot import *  lineEQ = lambda k,a: log(a)+(k-a)/a x1 = linspace(0,7,100) y1 = log(x1) x2 = linspace(-1.5,4,3) y2 = lineEQ(x2,1.5) x3 = [1.5,2.5,2.5] y3 = [][0],1.5), lineEQ(x3[0],1.5), lineEQ(x3[1],1.5)]  fig = figure(figsize=(5,3)) ax = fig.add_subplot(111)  for direction in ["left","bottom"]: 	ax.spines[direction].set_position('zero') 	ax.spines[direction].set_smart_bounds(True) for direction in ["right","top"]: 	ax.spines[direction].set_color('none') ax.xaxis.set_ticks_position('bottom') ax.yaxis.set_ticks_position('left')  ax.grid(False) ax.set_xticks([0,1.5,3,4,5]) ax.set_yticks([-2,-1,1]) ax.set_ylim(-2.2,1.5) ax.set_xlim(-1,5.5) ax.plot(x1,y1,'g',linewidth=1.) ax.plot(x2,y2,'k',linewidth=1.) ax.plot(x3,y3,'k--',linewidth=1.) ax.plot(1.5,log(1.5),'ro') ax.text(5.5,.2,"x") ax.text(0.1,1.5,"y") ax.text(4,1,r"$f(x)=\ln(x)$") ax.text(2,.175,"1",fontsize=7) ax.text(2.6,.5,r"$f^'(x)=\frac{1}{x}$",fontsize=12) ax.minorticks_on() #fig.show() fig.savefig("Logarithm_derivative.svg",bbox_inches="tight",\ 	pad_inches=.15)