for 4) define the function as f(x)=x, when x<0, f(x)=x^2 when 0<=x<1 and f(x)=1, 1<=x<infinity...check weder the function is continuous at x=0,1...at x=0, f(0-)=f(0+)=0...similarly at x=1, f(1-)=f(1+)=1...hence the function is continuous at x=0 and x=1...thus the function is continuous for every x in R...also u can draw the graph and check..!!!
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