Results 1 to 4 of 4

- November 24th 2007, 03:11 AM #1

- Joined
- Oct 2006
- Posts
- 78

## Logarithme Help

Hello Guys i have a logarithme lesson, and our teacher gave us some exercices but he didn't explain all the lesson.

compare without a calculater:

Ln7 and ln2 + ln 3

For me: 7>3+5 --> Ln7>ln5

3+ln (radical)e and 4 ? well i don't know how to compare it.

Resolve this:

lnx =1 ; ln 2x=0 ; lnx=-1 ; lnx=3 ( what i have to do here)??

ln(x-3)=ln(x+7)-ln(x+1)??

ln(x^2-2x-3) = ln(x+7)

the teacher told us to do them and he gave us this

ln(ab) = ln (a) +ln(b) but i can't do them....

Please help me i have many exercices like these and when somebody could help me i guess i can solve the others ones

Many thanks in advance

- November 24th 2007, 05:34 AM #2

- November 24th 2007, 06:18 AM #3

- Joined
- Oct 2006
- Posts
- 78

- November 26th 2007, 09:12 AM #4

- Joined
- Oct 2006
- Posts
- 78

i solved this:

Ln(2+ radical 3)^30 + Ln(2+radical 3)^3 my result is 0

(x+2)Ln(x+2) i got x = -1

But i need Help with this Guys

Ln(x^2 - 4)=Ln5 + 2Ln3

Ln(Radical) 3-x + Ln(radical)x+1=Ln(radical)10-6x --> should i make them ^2?

system:

x+y=30

Lnx +lny=3Ln6

i did the resr but one question how to find the derivebality of this

Ln=[1-x^2]

p.s For the Last question [ ] = sorry about the ''z'' LOL it's Nothing

Thanks Now i am starting to love math and my teacher told my mum that i am contribution at class