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# C4 - Quick Question Watch

1. [ 2 ln 3 - 2 ln 4 ] - [ 2ln 1 - 2 ln 2 ]

= 2ln3 - 2 ln 4 + 2 ln 2

Is this correct ?
2. (Original post by IShouldBeRevising_)
[ 2 ln 3 - 2 ln 4 ] - [ 2ln 1 - 2 ln 2 ]

= 2ln3 - 2 ln 4 + 2 ln 2

Is this correct ?
Yes but you can reduce this to a single logarithm.
3. (Original post by Mr M)
Yes but you can reduce this to a single logarithm.
The thing is

I don't see how because

I got 2ln 3 - 2ln4 + 2ln0.5

I don't understand how the ( - ) in the second bracket can turn positive because if you do this using integers it does't work?
4. (Original post by IShouldBeRevising_)
The thing is

I don't see how because

I got 2ln 3 - 2ln4 + 2ln0.5

I don't understand how the ( - ) in the second bracket can turn positive because if you do this using integers it does't work?
you should have got -2ln(0.5) = -2ln(1/2) = -2ln1 + 2ln2 = 2ln2 because ln 1 = 0.
5. (Original post by davros)
you should have got -2ln(0.5) = -2ln(1/2) = -2ln1 + 2ln2 = 2ln2 because ln 1 = 0.
Yeah thanks... I'm glad I asked this question I had it in my head that the two (-) cancelled out and therefore the second bracket was 2ln1 + 2ln 2 = 2ln2

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