a particle is projected from a point P on a horizontal plane with initial speed 35 m/s at an angle a to the plane. show that if x and y are the horizontal and vertical distances of the particle from P then 250y=250(tan a)x-(1-tan^2 a)x^2

im not sure where to go with this but i was making the equation 35sin a t-4.9t^2=y and x=35cos a t dont no where to go from here