PLz step by stepSolutionCHeck for injective property Let fxf

PLz step by step

CHeck for injective property

Let, f(x)=f(y)

x^2=y^2

(x-y)(x+y)

x=y or x=-y

x=-y is not possible because x and y are both positive

So, x=y

Hence, k is injective

Check for surjective property

LEt ,x>=0 be in Q

So, sqrt{x} is well defined but it need not belong to Q+

eg, x=2 belong to Q

But, sqrt{2} does not belong to Q

So, x=2 does not belong to range of k

Hence, k is not surjective

So k is not a bijection