testbook

Question

explain this i am not able to understand even question. ans is c.

Comments

f is constant(try to make a graph on the basis of info given in first line, u wil easily understand from graph)

first make a continuese function

then when u give it integer values u will get a constant line on y axis.

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It is given that f is continuous,which means f(x) in [a,b] can be drawn without taking pen from the paper (but, sharp points are not possible (see |x| graph) ), in other words , it is differentiable in that interval.

Also, it is provided that f(x) is an integer , which means , there will be discontinuities or sharp points occur , if f(x) is not constant in [a,b]. Since f(x) is continuous in [a,b] , there will be no sharp points or discontinuity , therefore it is constant.