If `R=([1+((dy)/(dx))^2]^(3//2))/((d^2y)/(dx2))` , then`R^(2//3)` can be put in the form of `1/(((d^2y)/(dx^2))^(2//3))+1/(((d^2x)/(dy^2))^(2//3))` b. `1/(((d^2y)/(dx^2))^(2//3))-1/(((d^2x)/(dy^2))^(2//3))` c. `2/(((d^2y)/(dx^2))^(2//3))+2/(((d^2x)/(dy^2))^(2//3))` d. `1/(((d^2y)/(dx^2))^(2//3))dot1/(((d^2x)/(dy^2))^(2//3))`