not sure where to post this

[red and white kop!]

find the equation of the tangent and normal of the curve y=x^2 + 5 where x = 0
this is simple and i have no problem finding the gradient and equation of the tangent, but the gradient of the normal is not defined (divided by zero) and i do not know what this means when introduced into the equation y-y1 = m (x - x1)

 

[Deleted member 4993]

find the equation of the tangent and normal of the curve y=x^2 + 5 where x = 0
this is simple and i have no problem finding the gradient and equation of the tangent, but the gradient of the normal is not defined (divided by zero) and i do not know what this means when introduced into the equation y-y1 = m (x - x1)

Sketch the curve and the normal/tangent at the given point. The answer will jump out at you.

The line

x = Constant

has an undefined gradient.

So what is "x" for your normal line?

i do not know what this means when introduced into the equation y-y1 = m (x - x1)

This means that - that equation cannot be used blindly.

 

[red and white kop!]

so
horizontal lines have gradient zero
and vertical lines have gradient undefined
and this is always the case
am i right?

 

[Denis]

Yessssssss....................
http://www.onemathematicalcat.org/algeb ... _lines.htm

 

[red and white kop!]

thank you