If yy varies inversely as the square of xx and y=4y=4 when x=5x=5, what is yy when xx is 22?
1 Answer
Jun 6, 2017
Explanation:
"the initial statement is " yprop1/x^2the initial statement is y∝1x2
"to convert to an equation, multiply by k, the constant"to convert to an equation, multiply by k, the constant
"of variation"of variation
rArry=kxx1/x^2=k/x^2⇒y=k×1x2=kx2
"to find k use the given condition"to find k use the given condition
y=4" when " x=5y=4 when x=5
y=k/x^2rArrk=x^2y=5^2xx4=100y=kx2⇒k=x2y=52×4=100
"the equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(y=100/(x^2))color(white)(2/2)|)))
"when "x=2
rArry=100/(2^2)=100/4=25