I need help on these!!!
2 answers:
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Answer:
Step-by-step explanation:
<em>Given:</em>
The set A = {5, 13, 17, 20}
<em>Question: </em>
Find the number of subsets of A
Find the number of proper subsets of A
<em>Simple solution by counting:</em>
Subset of A that has 0 element:
{∅} - 1 set
Subset of A that has 1 element:
{5}, {13}, {17}, {20} - 4 sets
Subset of A that has 2 elements:
{5, 13}, {5, 17}, {5, 20}, {13, 17}, {13, 20}, {17, 20} - 6 sets
Subset of A that has 3 elements:
{5, 13, 17}, {5, 13, 20}, {5, 17, 20}, {13, 17, 20} - 4 sets
Subset of A that has 4 elements:
{5, 13, 17, 20} - 1 set
In total, the number of subsets of A: N = 1 + 4 + 6 + 4 + 1 = 16
The number of proper subsets (all of subsets, except subset which is equal to original set A): N = 16 - 1 = 15
<u><em>Key-point:</em></u>
The counting method might be used for finding the number of subsets when the original set contains few elements.
The question is that, for a set that contains many elements, how to find out the number of subsets?
The answer is that: there is a fix formula to calculate the total number () of subsets of a set containing
elements: N =
With original set A = {5, 13, 17, 20}, there are 4 elements belonged to A.
=> Number of subsets of A: N =
(same result as using counting method)
<em>Brief proof of formula: N = </em><em />
Each element of original set is considered in 2 status: existed or not.
If existed => fill that element in.
If not => leave empty.
For i.e.: empty subset means that all elements are selected as not existed, subset with 1 element means that all elements are selected as not existed, except 1 element, ... and so on.
=> From the point of view of a permutation problem, for each element in original set, there are 2 ways to select: existed or not. There are elements in total. => There are
ways to select, or in other words, there are
subsets.
Hope this helps!
:)
Answer:
Given that,
The function is,
To find: To find the slope of the secant line from x1=0 and x2=4
Explanation:
First we find the corresponding y values that is y1 and y2 for the given x1 and x2 respectively.
we get,
Whwn x1=0,
When x2=4, we get,
To find the slope of the line passing the points (0,555), (4,1099.8)
we know that,
Slope of the line passing through the points (x1,y1) and (x2,y2)
we get,
Answer is:
Slope of the secant line from x1=0 and x2=4 is 136.2.