SOLUTION: y is directly proportional to x^2 and y=a for a particular value of x. Find an expression for y in terms of a, when this value of x is doubled. Please help me with this!! Thank

Question 1078679: y is directly proportional to x^2 and y=a for a particular value of x. Find an expression for y in terms of a, when this value of x is doubled.

Please help me with this!! Thank you.
Answer by akch2002(12) (Show Source): You can put this solution on YOUR website!
y is directly proportional to x^2 and y=a for a particular value of x. Find an expression for y in terms of a, when this value of x is doubled.
we can write
y =kx^2 where k is proportionality constant.
further
a = kx^2 ---- (1)
We have to find when x is doubled.
Let it be y1.
Hence, y1= k(2x)^2 = k*4x^2 ---- (2)
Putting value of k from 1, we get
y1 = (a/x^2)*4x^2
= 4a will be the value of when at double value.
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