If `P(x ,y)` is any point on the ellipse `16 x^2+25 y^2=400` and `F_1=(3,0)F_2=(-3,0)` , then find the value of `P F_1+P F_2dot`

If P is any point on the ellipse 16 x^(2)+25 y^(2)=400 then P S_(1)+P S_(2)= , where S_(1) and S_(2) are the foci of the ellipse.

Find the eccentricity of the ellipse 25x^2+16y^2=400 .

If P is any point on the ellipse (x^(2))/(36) + (y^(2))/(16) = 1 , and S and S' are the foci, then PS + PS' =

If F_(1) is (3, 0) and F_(2) is (-3,0) and P is any point on the ellipse (x^(2))/(25)+(y^(2))/(16)=1 , then |PF_(1)|+|PF_(2)| equals :

If P=(x, y), F_(1)=(3,0), F_(2)=(-3,0) and 16 x^(2)+25 y^(2)=400 then P F_(1)+P F_(2)=

Let P be a variable point on the ellipse x^(2)/25 + y^(2)/16 = 1 with foci at S and S'. If A be the area of triangle PSS' then the maximum value of A, is

If P is the length of perpendicluar drawn from the origin to any normal to the ellipse x^(2)/25+y^(2)/16=1 , then the maximum value of p is

If p and q are the roots of the equations x^(2) - 3x+ 2 = 0 , find the value of (1)/(p) - (1)/(q)

If f(x)=f'(x) and f(1) =2 , then f(3) equals :

. If P Q and P R are the tangents from P to the ellipse (x^(2))/(2)+y^(2)=1 , and the equation of Q R is x+3 y=1 , then P =