A frog jumps into a pond at (0, 0), creating a ripple effect with a radius that increases at a rate of 7 cm/s. What is the equation of the circle after 6 seconds?

Answer 1

7 cm/sec times 6 sec = 42 cm radius

x^2 +y^2 = 42^2 after 6 seconds

x^2 +y^2 = 1764

standard equation for a circle is (x-h)^2 + (y-k)^2 = r^2

where (h,k) = the center and r =radius of the circle

(x-0)^2 + (y-0)^2 = 42^2

becomes

x^2 + y^2 = 1764