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Question about logarithms log math?
Im totally lost with this...Im going to copy the question word by word... Please help...Correct answer gets 10 pts..
A black hole is a region in space where objects seem to disappear.A formula in the study of black holes is the Schwarzchild formula.
R= 2GM
-------------
c^2
Based on the laws of logarithms, log B can be represented by
A)2 logG + logM - log 2c
B)log 2G + log M- log 2c
C)log 2+ log G+ log M - 2 log c
D)2 log GM- 2 log c
If you may, can you explain how you got to the answer. Thanks I appreciate it much.
SORRY, GEEZA,,,,I meant to say
'Based on the laws of logarithms, log R can be represented by..'
10 Answers
- Marley KLv 71 decade agoFavorite Answer
The answer is C) log 2 + log G + log M - 2 log c
All I did was apply the three properties of logs:
for the numerator: log AB = log A + log B
for the denominator: log A/B = log A - log B
for the exponent: log A^p = p log A
that's it! :) (oh, I had to assume by B in your question you meant the R in the formula, right?)
- Anonymous1 decade ago
So is the formula R = 2GM / (c^2)? And do you mean the log(R), not log(B)?
If that's the case, then you need to learn the rules of logs, which apply to logs of any base:
log(ab) = log(a) + log(b)
log(a/b) = log(a) - log(b)
log(a^b) = b log(a)
Apply the first two rules to split log(2GM / (c^2)) into four different log terms, then use the third rule to simplify the " - log(c^2)" at the end.
- ?Lv 71 decade ago
I don't know where logB would come from. The Schwarzchild formula calclates the radius of a black hole (the Schwarzchild radius, written r sub s. The formula is
r = 2 G m / c^2
where r is the radius, G is the gravitational constant, m is the mass and c is the speed of light.
log B is missing!
- 1 decade ago
i will assume that in your question you meant to type log R not log B.
first take the log of both sides so log R = log(2GM/c^2)
and now apply the different rules for logs. there are the rules. i dont know the names:
log (a*b) = log a + log b
log (a/b) = log a - log b
log (a^b) = b*log a
hope this helps.
remember that these apply to any base logarithm.
read your math book!!!
Source(s): engineering student - stanschimLv 71 decade ago
C is the correct answer.
The logarithm of a product is the sum of the logarithms; that's how you get the first three terms in C. When division is involved, you can subtract the logarithm; also when a power is involved you can multiply by the exponent. That's how the third term is developed.
- 1 decade ago
Geezah is correct, they just didn't fully answer the question.
-log(c^2) = -2log(c) so the answer is C).
- NorthstarLv 71 decade ago
The answer is C.
I assume you mean log(R).
Use the rules of logs.
log(ab) = log(a) + log(b)
log(a/b) = log(a) - log(b)
log(a^b) = b log(a)
Now apply the rules to the problem.
R = 2GM/c²
log(R) = log(2GM/c²) = log(2GM) - log(c²)
= log(2) + log(G) + log(M) - 2log(c)
The answer is C.