Answer:
Consider f: N → N defined by f(0)=0 and f(n)=n-1 for all n>0.
Step-by-step explanation:
First we will prove that f is surjective. Let y∈N be any natural number. Define x as the number x=y+1. Then x∈N, and f(x)=x-1=(y+1)-1=y. We conclude that f is surjective.
However, f is not injective. Take x1=0 and x2=1. Then x1≠x2 but f(x1)=0 and f(x2)=x2-1=1-1=0. We have shown that there are two natural numbers x1,x2 such that x1≠x2 but f(x1)=f(x2), that is, f is not injective.
Note:
If 0∉N in your definition of natural numbers, the same reasoning works with the function f: N → N defined by f(1)=1 and f(n)=n-1 for all n>1. The only difference is that you consider x1=1, x2=2 for the injectivity.
The Correct Answer On Edgen Is
<u>A) Linear pair postulate.</u>
Answer:
-3
Step-by-step explanation:
you go down from the dot left most and you count towards the line that the second dot falls on and count over too it
Answer:
Step-by-step explanation:
It could also be 
depending on how the problem is actually set up.
W - width
l - length
p - perimeter
The perimeter is 72 cm (p=72).
The length is twice the width (l=2w).
The formula for perimeter is 2w+2l=P.
Check the answer:
The length of the photo is 24 cm, the width of the photo is 12 cm.
