View Full Version : Calculus Logs
claire3158
Jul 29, 2009, 04:07 PM
1. Log(2)5 +log(2)(X^2-1) - log(2) (X-1)
2. 3^2log(3)5
3. 2log(10) root of X +3log(10) X^1/3
Solving for the indicated variable... solve this equation for A..
4.x/a + y/b + z/c=1
galactus
Jul 29, 2009, 04:35 PM
4.\frac{x}{a} + \frac{y}{b} + \frac{z}{c}=1
The LCD is abc. Multiply through by abc:
\not{a}bc\cdot \frac{x}{\not{a}}+a\not{b}c\cdot \frac{y}{\not{b}}+ab\not{c}\cdot \frac{z}{\not{c}}=abc
bcx+acy+abz=abc
bcx=abc-acy-abz
x=a-\frac{ay}{b}-\frac{az}{c}
Unknown008
Jul 30, 2009, 10:45 AM
No need to post on different topics... nor twice in the same topic
https://www.askmehelpdesk.com/math-sciences/solving-calculus-logs-381283.html
Anyway, I wasn't aware of that, and I already answered it there.
galactus, the question was 'solving for a', though I believe it is 'making a the subject of formula'.
\frac xa + \frac yb + \frac zc = 1
Send everything except x/a on the right.
\frac xa = 1- \frac yb - \frac zc
Make as a single fraction:
\frac xa = \frac{bc-yc-zb}{cb}
'Cross multiply everything' or invert everything:
\frac ax = \frac{bc}{bc-yc-zb}
Then, multiply by x:
a = \frac{xbc}{bc-yc-zb}
galactus
Jul 30, 2009, 10:57 AM
So right:o
I solved for x. Oh well, the method is pretty much the same.
I tried giving you a greenie, but of course, it won't let me. I have been spreading it around, but it still won't allow me to give you a greenie. :confused:
Unknown008
Jul 30, 2009, 10:59 AM
Same thing here for the 'Derivatives' thread... :( Your recent greenie on Survivorboi's thread I gave you prevents me from giving you another one now. I have to greenie some more people...
galactus
Jul 30, 2009, 11:06 AM
I don't like that. It's bogus, man:)