Question

If t is the parameter for one end of a focal chord of the parabola y^2=4ax than its length is

Answer 1

Following are the options for this question:

(a) a(t+1t)2

(b) a(t−1t)2

(c) a(t+1t)

(d)  a(t−1t)

The correct answer for this question is:

option A : a(t+1t)2

If there is any confusion, please leave a comment below.

Answer 2

solution:

Y∧2 = 4ax

t1t2 = 1

AB = AS + BS

     = at12 +a + at22 + a

     = a(t12 + t22 + 2)

     =  a( t12 + 1/t1 + 2)

     = a( t1 +1/t1)2