What is the solution of the system of linear equations below?
1 answer:
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Answer:
53 lies between 7.2² and 7.3²
Step-by-step explanation:
Estimating a root to the nearest tenth can be done a number of ways. The method shown here is to identify the tenths whose squares bracket the value of interest.
You have answered the questions of parts 1 to 3.
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<h3>4.</h3>You are given that ...
7.2² = 51.84
7.3² = 53.29
This means 53 lies between 7.2² and 7.3², so √53 lies between 7.2 and 7.3.
53 is closer to 7.3², so √53 will be closer to 7.3 than to 7.2.
7.3 is a good estimate of √53 to the tenths place.
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<em>Additional comment</em>
For an integer n that is the sum of a perfect square (s²) and a remainder (r), the square root is between ...
s +r/(2s+1) < √n < s +r/(2s)
For n = 53 = 7² +4, this means ...
7 +4/15 < √53 < 7 +4/14
7.267 < √53 < 7.286
Either way, √53 ≈ 7.3.
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The root is actually equal to the continued fraction ...
9514 1404 393
Answer:
obtuse
Step-by-step explanation:
The law of cosines tells you ...
b² = a² +c² -2ac·cos(B)
Substituting for a²+c² using the given equation, we have ...
b² = b²·cos(B)² -2ac·cos(B)
We can subtract b² to get a quadratic in standard form for cos(B).
b²·cos(B)² -2ac·cos(B) -b² = 0
Solving this using the quadratic formula gives ...
The fraction ac/b² is always positive, so the term on the right (the square root) is always greater than 1. The value of cos(B) cannot be greater than 1, so the only viable value for cos(B) is ...
The value of the radical is necessarily greater than ac/b², so cos(B) is necessarily negative. When cos(B) < 0, B > 90°. The triangle is obtuse.