Consider any point P on the ellipse x ^2 25 + y ^2 9 =1 in the first quadrant. Let r and s represent its distances from (4,0) and (-4,0) respectively, then (r+s) is equal to

Step-by-step solution

x^2 25 + y^2 9 =1 Put x =3 aligned & 9 25 + y^2 9 =1 & y = 12 5 & P =(3,12 / 5) & r = PO = (4-3)^2+ (0- 12 5 )^2 & =13 / 5 & ~S = PO ^ = (-4-3)^2+ (0- 12 5 )^2 & =37 / 5 & r+s= 13 5 + 37 5 = 50 5 =10 unit aligned