A certain element has a half life of 4.5 billion years. a. You find a rock containing a mixture of the element and lead. You det
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11 school days are left.
In the attached picture of a calendar, I marked the days the person has left. There are 11.
Answer:
462
Step-by-step explanation:
Rectangular Prism: 7 x 8 x 6 = 336
Triangular Prism: (0.5 x 7 x 6) x 6 = 126
336 + 126 = 462
Answer: First, injective means that for every y, there is only one x such f(x) = y, and surjective means that if f is a function that goes from the set {x} to the set {y}, for every element y in the codomain there is at least one element x in the domain such f(x) = y
(a) f:R----> + R given by f(x) = x2 (i guess you written )
The function is not injective, because f(-2) = f(2), and is surjective, because the codomain is +R, and is always a positive real number.
(b) f:N----> + N given by f(n) = n2 (i guess you written )
As the naturals have no negative numbers, in this case the function is injective, but isn't surjective, because there is no number that when squared is equal to 5, for example.
(c) f: Zx Z → Z given by f(n, k) = n +k:
here the domain is of the form (n,k) and the function is n +k, so the numbers (z,w) and (w,z) return the same value when evaluated in f, then f is not injective. And is easy to see that f is surjective, because in the sum you can reach al the integers on the codomain.