Maths homework fail...
 

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[Closed] Maths homework fail!

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Posts: 8
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Mr Thicky-pants here couldn't rearrange the following, can someone show me line by line how it should be done please:

v/(4x^2) = w/y

x=?


 
Posted : 02/12/2011 8:50 am
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v/(4x^2) = w/y
v = (w/y)*(4x^2)
v/(w/y)=(4x^2)
(v*y)/w =(4x^2)
(v*y)/4w =x^2
x=((v*y)/4w)^0.5
(^0.5 is to the power of 0.5, same as square root)

Edit: assuming that the (4x^2) is 4*x^2, not (4x)^2


 
Posted : 02/12/2011 8:53 am
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x=(vy/4w)^0.5


 
Posted : 02/12/2011 8:53 am
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Rather than line by line I tend do a quick cheat on ones like this and put some real numbers in so -

6 / 3 = 4 / 2 is the same layout as -> v / (4x^2) = w / y

3 = (6* 2) /4

That way you can do a quick sanity check to see the equation is still correct.

Sticking the symbols back in

4x^2 = (v*y)/w

x^2 = ((v*y)/w)/4

x = Sqrt((v*y)/w)/4)

or

x = Sqrt((v*y)/(4w))


 
Posted : 02/12/2011 9:01 am
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Thank you all, I can now help my son with the rest of his homework 😀


 
Posted : 02/12/2011 9:15 am