This one is not clear in my opinion.
I have two equations that I want to reaarange, one a power, the other a log. I can solve the orignal equations but am getting stuck trying to make x the subject. Any help would be appreciated.
eq. 1: y= 4.3316x0.4671
To solve this (for x=8) I did the following: 4.3316 * 80.4671
= 8^(1/10 000) PWR 4671
= 4.3316 *2.64
I think this is right but don't know how to rearrange to get x= ?
Eq 2. y=9.5818ln(x) - 9.5878
Can solve this ok but stuck on same point - getting x=
I assume the problem (1) is to solve for x. (If you don't use LaTeX, at least use "^" to indicate powers.)
Start with the obvious: divide both sides by 4.3316:
and then take the .4671 root of both sides: .
No logarithm need.
If the x had been in the exponent, then you would need the logarithm:
Sorry to be stupid but I can't seem to get a sensible answer drom the above equation that you kindly showed me how to rearrange. When I solve the original equation for y using a series of values for x, I can't then use those same values of y to get the corresponding values of x that I used - I end up with insanely large values for x.
What I would give to be good at maths
Ok. Here is my problem. Let's say in the original equation x =49. If I am correct this would give a value for y of 27.7. So now I want to use the rearranged equation, using this value of y (27.7), to get back to the original value of x I used (49) - to check I understand how to do it. This is where I am stuck. Looking at the equation, e is the base, which is ln or 2.718281828. Am I right here? y+9.5878/9.5818 is the power? This produces absurdly large anwers. I'm sure there is something pretty fundamental that I am not understanding?!