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maths in a program
Hi guys.
I know this isn't code but maths to go into a program, I need to know which is right.
I have a couple of formulae which need rearranging:
1) Make r the subject of.
a = 2pi(r + h)
first multiply out the bracket 2pir + 2pih = a
then subtract 2pih from both sides 2pir = a - 2pih
now divide both sides by 2pi r = a - 2pih / 2ip ( this is the answer that I have ).
2) make x the subject of.
5(x + 2) = y
first multiply out the bracket 5x + 10 = y
then subtract 10 from both sides 5x = y - 10
now divide both sides by 5 x = y - 10 / 5 ( stop here with this answer or do the maths on the right hand side giving x = y / 5 - 2 ) where do I stop with the answer.
in question 1 I stopped as soon as the required subject was on its own but in question 2 i got the required subject on its own and then proceeded to simplify the maths on the rhs (which way is correct)
THANKS for the help (learner wanting to be a master).
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Firstly, you went the long way around to get 'r' and 'x' the subjects.
a= 2pi(r + h)
a/2pi = r+h
r = a/2pi -h
5(x + 2) = y
x + 2 = y/5
x = y/5 - 2
Simple. But if you understand the other way better stick to that. Second, if 'x' is the subject to be, go all the way, don't stop halfway through.
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anthony,
kwigibo's answers are correct, whereas yours are missing parentheses. Your answers should be:
r = (a - 2pih) / 2pi
and
x = (y - 10) / 5,
which are equal to kwigibo's.