$AB$ is a chord of the parabola $y^{2} = 4ax$ with vertex at $A$.$BC$ is drawn perpendicular to $AB$ meeting the axes at $C$. The projection of $BC$ on the axis of the parabola is

Question

Dr. Abubacker · Accepted Answer

(c)
In $\mathrm{\Delta}\ ABD$, we have
$	an{	heta = \frac{y}{x}\ \ \ \ldots(i)}$
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In $\mathrm{\Delta}BCD$, we have
$	an{(90{^\circ} - 	heta) = \frac{y}{CD}}$
$\Rightarrow CD = y	an{	heta = \frac{y^{2}}{x}\ \ \lbrack using\ Eq.(i)brack}$
$\Rightarrow \ CD = \frac{4ax}{x} = 4a$

Q. $AB$ is a chord of the parabola $y^{2} = 4ax$ with vertex at $A$.$BC$ is drawn perpendicular to $AB$ meeting the axes at $C$. The projection of $BC$ on the axis of the parabola is

Explanation

Reviewed by Dr. Abubacker

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