Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 2007-09-08 05:12:58

Identity
Member
Registered: 2007-04-18
Posts: 934

Three loggy questions

1. Solve the equation

2.

, show that

3. Evaluate:

Thanks!

Last edited by Identity (2007-09-08 05:13:20)

Offline

#2 2007-09-08 06:09:20

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: Three loggy questions

I hope I didn't make any mistakes...

Because log(a) + log(b) = log(ab)

Because 10^log(a) = a

So the positive value is x = 1.


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

Offline

#3 2007-09-08 06:40:54

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: Three loggy questions

Ok, I know there's gotta be an easier way to do this...

so:

Moving on...

And now the finale:

Possibly one of the most round-about ways of getting the answer...


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

Offline

#4 2007-09-08 08:55:48

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: Three loggy questions

The last one's a bit easier.

2log12 + 3 log5 - log15 - log150
log(12²) + log(5³) - log15 - log150
log[(2x2x3x2x2x3 x 5x5x5)/(3x5 x 2x5x3x5)]

log[2x2x2]

3


Why did the vector cross the road?
It wanted to be normal.

Offline

#5 2007-09-08 14:28:42

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: Three loggy questions

Thanks, the 2nd question seems pretty hard lol

Offline

#6 2007-09-08 16:34:28

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: Three loggy questions

Identity wrote:

Thanks, the 2nd question seems pretty hard lol

I'm sure there's an easier way to do it, I just always take the long way around.


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

Offline

#7 2007-09-12 15:12:30

George,Y
Member
Registered: 2006-03-12
Posts: 1,379

Re: Three loggy questions

2nd question:


X'(y-Xβ)=0

Offline

Board footer

Powered by FluxBB