Please help me with this sum
1 answer:
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Answer:
-1875
Step-by-step explanation:
An arithmetic sequence has a common difference as a sequence. Here the common differnece is -11.
So our sequence so far looks like,
(57,46,35,24....). We know the last term of the sequence is -207 and we need to find the nth term of that series so we use arithmetic sequence
where a1 is the inital value,
d is the common differnece and n is the nth term.
We need to find the nth term so
So the 25th term of a arithmetic sequence is last term, now we can use the sum of arithmetic sequence
which is
Answer: 130.8 degrees
Explanation:
The problem can be solved by using the cosine theorem:
(1)
where
a,b,c are the lengths of the three sides of the triangle
is the angle between b and c
In this problem, we can identify a,b,c, with:
a = XZ = 11.05
b = XY = 6.32
c = YZ = 5.83
So, the angle corresponds to the angle m∠Y. Re-arranging eq.(1), we find
So, the angle is