Hi everyone. I have a question that is troubling me.
Let's have a rational function, for example Q(x)/P(x), and decide for some reason to decompose it into a lovely sum of constants over expressions of the type (x-a). We work in real numbers, and P is decomposable in R.
Q(x)/P(x) = A/(x-a) + B/(x-b) ... etc
So people tell me that now we multiply by P(x), make Q(x) = A* [P(x)/(x-a)] + B * [P(x)/(x-b)] ... ,
then suppose x = a (that is in order to eliminate the term including A) and so on.
How come we multiply by (x-a) but don't say that a is a prohibited value for x? (Thinking)
Sep 6th 2009, 08:39 AM
Please do not post algebra problems in the wrong subforum, head over to the pre university forum, and post this problem in the algebra section.