Determine the x and y components of velocity of the car if it travels with a constant speed v on the curved path

a. vx = v/r, vy = v(2 p a/b)cos(2 p x/b)/r  
b. vx = v r, vy = v(2 p a/b)cos(2 p x/b) r
c. vx = v/r, vy = v(2 p a/b)cos(2 p x/b) r
d. vx = v r, vy = v(2 p a/b)cos(2 p x/b)/r

where r = (1 + (cos(2 p x/b) (2 p a/b))2)-0.5

vx = dx/dt
vy = dy/dt = (dy/dx)(dx/dt)
vy = vx(2 p a/b)cos(2 p x/b)

v = (vy2 + vx2)0.5
v = vx/r

vx = v r

vy = v r (2 p a/b)cos(2 p x/b)

The components of velocity are  vx = v r, 
vy = v r (2 p a/b)cos(2 p x/b)