23.9 is the answer have a nice day
Let's start from what we know.
Note that:
(sign of last term will be + when n is even and - when n is odd).
Sum is finite so we can split it into two sums, first
with only positive trems (squares of even numbers) and second
with negative (squares of odd numbers). So:
And now the proof.
1) n is even.
In this case, both
and
have
terms. For example if n=8 then:
Generally, there will be:
Now, calculate our sum:
So in this case we prove, that:
2) n is odd.
Here,
has more terms than
. For example if n=7 then:
So there is
terms in
,
terms in
and:
Now, we can calculate our sum:
We consider all possible n so we prove that:
Answer:
(2, 5).
Step-by-step explanation:
The length of the line joining the first 2 points = (5 - 3) = 2 units. This is a vertical line because the 2 x coordinates ( -6 and - 6) are equal.
The line joining ( -6 , 3) and (2 , 3) is horizontal and is 2 - -6 = 8 units long.
Because we have a rectangle the point we need to find must have x coordinate of 2 and the y coordinate will be 2 more than the y coordinate 3.
.So it is (2, 5),
If u work it out and both sides don't equal, then there is no solution.
Example :
2x + 4 = 2x + 6
2x - 2x = 6 - 4
0 = 2....this is incorrect...therefore, there is no solution
Answer:
30cm
Step-by-step explanation:
Assuming that the thickness of the books is 2cm (This is a reasonable assumption, as books are almost always longer and wider than they are thick, and assuming that the books are stacked flat on top of one another, faces up or down, and not sideways, the question becomes 'What is the height of 15 books stacked on top of one another, if each book is 2cm thick?' The answer to this question is 15*2 or 30.