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The variable z varies jointly with x and y and inversely with the square of t. Also, z=5 when x=2, y=-3, and t=1/2. Write a function such that f(y)=t when x=(-12)/(5z)^2 and z=2/5. 

 

I really need help with this problem, can you guys give it a try? Thank you!

 Sep 6, 2016
 #1
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z= kxy/t^2

 

5 = k*2*(-3)/(1/4).    Hence k = -5/24

 

z = -(5/24)xy/t^2

 

When x = -12/(5z)^2 then z = -(5/24)(-12)y/(5zt)^2 or z^3 = y/(10t^2)

 

With z = 2/5 we have 8/125 = y/(10t^2) so that t = (5/4)y^(1/2)

 

Hence if f(y) = (5/4)y^(1/2) then f(y) = t when the above conditions hold.

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 Sep 6, 2016

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