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Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 decade ago

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.

Update:

SORRY, GEEZA,,,,I meant to say

'Based on the laws of logarithms, log R can be represented by..'

10 Answers

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  • 1 decade ago
    Favorite 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?)

  • Anonymous
    1 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 7
    1 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!

  • 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
  • jaya
    Lv 4
    1 decade ago

    Answer is (c)

    log R = log 2 +log G + log M - 2 log C

  • 5 years ago

    )log 2+ log G+ log M - 2 log c

  • 1 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).

  • 1 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.

  • ?
    Lv 5
    1 decade ago

    Answer is C).

    B=2*G*M/c^2

    log(B)= log(2)+log(G)+log(m) - 2log(c)

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