How do I rearrange to make the exponent the subject of the expression?
Emily Wong
I find myself trying to work out something where the formula is something to the power of two things multiplied equals something else. A bit like this:
$a^{(b.c)}=d$
My math skill is insufficient for me to work out how to make one of the exponents the subject. I'm after:
b = some function of everything else.
I tried applying the b root to both sides and just twisted myself up into a mess that made no sense.
Would someone kindly explain like I'm twelve, the steps I need to take to make an exponent (b, in my case) the subject of the expression?
$\endgroup$1 Answer
$\begingroup$Take logarithms of both sides$$a^{bc}=d \implies bc\log(a)=\log(d)\implies b=\frac 1 c \frac{\log(d) } {\log(a) }$$
For sure, as @Jeanba commented, this implies that the arguments of the logarithmic function must be strictly greater than zero.
$\endgroup$ 2