Query regarding Mock test math Q.5 & Q.13

[Prianka Rit]

Hi Team, 

Can you clarify the concept of the two questions mentioned above? How the function is onto? And rest of are not? And how to get the clear concept about function? Function, the only part of the math syllabus, I am suffering from. Please help. 

[Malabika Guha Mustafi]

Trying to give reply , then Team will clarify. 

Function Types. mainly three types need to remember.

1.one to one ( Injective)

When for  each x value there is a distinct y value.[y is the function of x]

If two different x value generate same y value then the function is not injective. ( think about injection, no two persons are allowed for one injection)

2. Onto ( surjective)

Simple approach, just remember your range ( the value you will get from the function directly) should be same as co domain.( the domain of the y which is  function of x).

If your codomain defined as real number but the range is taking only integer or rational or natural number, then the function is not surjective  or onto. If your codomain defined as range of natural number but your range is not covered full range just picking few elements then also the function is not surjective.

3. Bijective

By definition , the  bijective function is injective and surjective[ both onto and one to one].

@ diya , I think now you can solve the problem of 5 and 13 by yourself. 

First try and if you face any difficulties then we will solve these together. All the best.