for the statement, find the constant of variation and the equation.
y varies directly as the cube of x; y=4 when x=2
find the constant of variation k.

Question

for the statement, find the constant of variation and the equation. 
y varies directly as the cube of x; y=4 when x=2
find the constant of variation k.

anonymous · Answer

help mee!

anonymous · Answer

Y varies directly as the cube of x means that the relation between y and x is of the form:
$$y=kx^3 ... (1)$$
Now, you should use the given point x=2,y=4 to find the value of k. That's:
$$4=k(2)^3 \implies 4=8k \implies k=2$$

anonymous · Answer

soo what would the direct variation equation be?

anonymous · Answer

Substitute k=2 in equation (1) and that's your variation equation:
$$y=2x^3$$

anonymous · Answer

ohh okay thanks!

anonymous · Answer

np