Q1 of 99 Page 59

Mark (√) against the correct answer in the following:

f : N → N : f(x) = 2x is


f(x) = 2x


For One - One


f(x1) = 2x1


f(x2) = 2x2


put f(x1) = f(x2) we get


2x1 = 2x2


Hence, if f(x1) = f(x2), x1 = x2


Function f is one - one


For Onto


f(x) = 2x


let f(x) = y, such that y∈N


2x = y


⇒


If y = 1


x =


which is not possible as x∈N


Hence, f is not onto., f is into


Hence, option b is correct

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 3

Mark (√) against the correct answer in the following:

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