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Mathematics

20140426_212157.jpg
How do u get from one step to the other??
My teacher explained but I forgot. :frown:
Reply 1
Avatar for rs232
rs232
Any context? ie the question you're trying to answer
Reply 2
Avatar for james22
james22
16
If it is a + then it is obvious. If it is a - then x=−ln(c+c2−1)=ln(1c+c2−1)x=-ln(c+\sqrt{c^2-1})=ln(\frac{1}{c+\sqrt{c^2-1}}).

Can you finish from here?

In future, you will likely get better responses by posting in the maths help forum.
(edited 9 years ago)
Reply 3
Avatar for RVNmax
RVNmax
19
EDIT: ignore this post! James 22 has pointed out that they are indeed equal.

Original post by WinOrDie
20140426_212157.jpg
How do u get from one step to the other??
My teacher explained but I forgot. :frown:


I wouldn't say that is correct in general terms. - No link between them. Like the poster 'rs232' said, it might just be true in this question, so it would be good if you could post the question.
(edited 9 years ago)
Reply 4
Avatar for james22
james22
16
Original post by rs232
Any context? ie the question you're trying to answer


Context does not matter.

Original post by RVNmax
I wouldn't say that is correct in general terms. - No link between them. Like the poster 'rs232' said, it might just be true in this question, so it would be good if you could post the question.


It is correct in general terms, provided c>=1.
Reply 5
Avatar for WinOrDie
WinOrDie
OP
1
Original post by james22
If it is a + then it is obvious. If it is a - then x=−ln(c+c2−1)=ln(1c+c2−1)x=-ln(c+\sqrt{c^2-1})=ln(\frac{1}{c+\sqrt{c^2-1}}).

Can you finish from here?

In future, you will likely get better responses by posting in the maths help forum.


Yeah you got the assumptionI shoulda mentioned.
And nope I don't think I can go on from there :/
maybe ln(1)- ln(the rest)
Reply 6
Avatar for james22
james22
16
Original post by WinOrDie
Yeah you got the assumptionI shoulda mentioned.
And nope I don't think I can go on from there :/
maybe ln(1)- ln(the rest)


Try rationalising teh denominator, you will find that there is some convenient cancelling that occurs.
Reply 7
Avatar for WinOrDie
WinOrDie
OP
1
Original post by james22
Try rationalising teh denominator, you will find that there is some convenient cancelling that occurs.


aah thanks mate ofcourse difference of two squares

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