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View Full Version : [Logarithms]Kepler's third law of planetary motion


anonymous12
Dec7-11, 07:59 PM
1. The problem statement, all variables and given/known data
Kepler's third law of planetary motion relates P, the period of a planet's orbit, to R, the planet's mean distance from the sun, through the equation log P = \frac{1}{2} (log K + 3log R), where K is a constant.

Rewrite the formula as a single logarithm.

2. Relevant equations
log P = \frac{1}{2} (log K + 3log R)

3. The attempt at a solution

Rewrite the formula as a single logarithm.
log P = \frac{1}{2} (log K + 3log R)
log P = \frac{1}{2} (log(KR^3))
log P = log K^\frac{1}{2} \cdot R^\frac{3}{2}

I have no idea what to do next.

4. The answer in the back of the textbook
log(\frac{K^{\frac{1}{2}} \cdot R^{\frac{3}{2} }}P)=0

Here I have no idea how they made the equation equal to 0. If anyone could help me I will be very grateful.

anonymous12
Dec7-11, 08:39 PM
Nevermind. I got it!

Mark44
Dec7-11, 08:42 PM
Glad we could help!