A chord BC is drawn in a parabola y2=4x such that x cordinate of C is twice that of B. Also OB makes 45∘ with x-axis. What is the projecton of BC on y-axis?
Given parabola is,
y2=4x
B≡(x,x)(since slope of OB is 1)
X coordinate of C=2 times x coordinate of B.
C≡(2x,y)
Since (x,x) lies on the parabola y2=4x,
x2=4x
⇒ x=4
i.e., B≡(4,4)
C≡(8,y1)
∴ projection of BC on x-axis =XC−XB
=4