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 2007-11-05 00:20:21

EPhillips1989
Member
Registered: 2007-11-03
Posts: 29

logs

hey i was just wondering what happens when you take logs of both sides of equations like the following

e^(3ix)=8e^(-PI/2i)

what happens to the 8??? please help asap xxxxxxx

Offline

#2 2007-11-05 01:01:58

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

Re: logs

Because the 8 is multiplied by the exponent, you can split it into a separate log, using the fact that log(ab) = loga + logb.

So, log[8e^(-π/2i)] = log8 + log(e^-π/2i) = log8 - π/2i.


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

Offline

#3 2007-11-05 01:06:20

EPhillips1989
Member
Registered: 2007-11-03
Posts: 29

Re: logs

i got that far do you know how to find x when

3ix=log8-Pi/2i??

Offline

#4 2007-11-05 01:13:35

EPhillips1989
Member
Registered: 2007-11-03
Posts: 29

Re: logs

iv got to
i(3x+Pi/2)-log8=0

Offline

Board footer

Powered by FluxBB