tangents to parabola y2=4ax makes an angle of 60 degree with the axis find its point of contact

the slope of a line which makes an angle of 60 deg with x-axis is m=tan60=3 the equation of the tangent is y=mx+c i.e. y=3.x+c ........(1) if the line (1) is tangent to the parabola y2=4ax , then c=am=a3 therefore the equation of the tangent is y=3.x+a3  if this straight line is tangent to the given parabola,  3x+a32=4.a.x3x2+a23+2*3.x*a3=4ax3x2+a23+2ax-4ax=09x2+a2-6ax=0(3x-a)2=03x-a=0x=a3
Therefore 
y=3.x+a3y=3.a3+a3y=2a3
thus the point of contact is a3,2a3 hope this helps you  

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As y^2 =4ax passes through origin(0,0) It's axis will be + X axis i.e. y=0
slope of tangent will be tan60=3^1/2 and line equation is y=0
therefore y - (3^1/2)x=0 is tangent's eq.


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