Hey I know this is really simple and silly, I used to find this really easy, I've been confused by a book and now feel rather stupid at not being able to even rearrange equations.. I get it right, right, right and then suddenly I get one written exactly upside down when compared to the book's answer.
Here's an upside down one:
to make the subject
Their answer was
I've spent a few hours rereading my chapters and getting a bit upset...what have I done wrong?
That's what my book says, my problem is...I don't understand... I mean...ARGH I have been royally confused. Firstly I was sticking to BEDMAS as I was taught (which is PEMDAS or whichever is used in the US) but half the time my book doesn't seem to...and now I'm all over the place.
If I just always always stick to BEDMAS/PEMDAS, will I ALWAYS get a correct rearrangement?? Because sometimes my book does not handle the exponents before multiplication for example. And then I want to stab it. Is there something I'm missing, something to do with isolating the subject or something?
PS thanks for taking the time to reply!
It looks like what you tried to do was to divide both sides by q1q2. But note that the r^2 was in the denominator, and suddenly, you put in the numerator, which is a no-no. . If you want to divide both sides by q1q2, then you're going to have to make the numerator on the right side 1, like this:
THIS STEP IS WRONG.
Although we've deviated from the work I showed above, we'll still get the same answer. If we now take the reciprocal of both sides we'll get
which does match what I have above.