Question

व्हाट वास द सऊदी अरबिया करेंसी कॉलेज ​

Answer 1

Explanation:

Correct option is D)

Given, f:N→N,  f(n)=(n+5)2

For one to one

f(n1)=f(n2)

⇒(n1+5)2=(n2+5)2

⇒(n1−n2)(n1+n2+10)=0

⇒n1=n2

∴   f is one to one.

When we put n=1,2,3,4,…∞, we will get

f(1)=36,f(2)=49,f(3)=64,f(4)=81,…

Here, we see that we do not get any pre-images of 1,2,3 etc.

Hence, f is not onto.