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See Answer

The signum (or sign) function, denoted by sgn, is defined by

a. Sketch the graph of this function.

b. Find each of the following limits or explain why it does not exist.

-1 if x<0 0 if x= 0 1 if x>0 sgn x = (i) lim sgn x x0+ (ii) lim sgn x X0- (iii) lim sgn x (iv) lim | sgn x|