tangents and normals (1 Viewer)

[enigma_1]

If y=1-2x is a tangent to x^2 = 4ay, find a and the point of contact.

Thanks,

btw I found a = -1/4

 

[braintic]

If y=1-2x is a tangent to x^2 = 4ay, find a and the point of contact.

Thanks,

btw I found a = -1/4

Sub in a=-1/4 to get x^2=-y, then solve simultaneously with y=1-2x

 

[alficio]

differentiate x^2=4ay against x.
2x = 4a*dy/dx
dy/dx = x/2a
But
dy/dx = -2
Solve for x since you know a .....etc.