Q7 7 The length of the latus-rectum of the parabola x = ay2 + by + c is - Maths -

Question

Q7
7 The length of the latus-rectum of the parabola x = ay2
+ by + c is

(a)  a 4              
                 
                 
           (b)  a 3 (c)  1
a                  
                 
                 
      (d)  1 4a

Manbar Singh · Accepted Answer

We have,    x = ay2 + by + c⇒ay2 + by = x - c⇒ay2  + ba = x - c⇒ay2  + ba + b24a2 - b24a2 = x - c⇒ay2  + ba + b24a2 - b24a = x - c⇒y + b2a2 = 1ax - c + b24a⇒y + b2a2 = 1ax - c - b24aComparing it with Y2 = 4AXSo, 4A = 1aHence, length of latus rectum = 4A = 1a

Q7 7.The length of the latus-rectum of the parabola x = ay2 + by + c is (a) a 4 (b) a 3 (c) 1 a (d) 1 4a

Q7
7.The length of the latus-rectum of the parabola x = ay² + by + c is

$(a) \frac{a}{4} (b) \frac{a}{3} (c) \frac{1}{a} (d) \frac{1}{4a}$