Needing help with functions

[oodanioo]

Hello! Since I haven't solved any examples using functions in a while, it's hard for me to solve this example. It would be really nice if someone could help me in some way and explain how i works.

Edited November 27, 2012 by oodanioo

[Amaton]

Hi,

 

I'm not familiar with the concept of "tangential lines" nor "cross points", and a Google search doesn't yield anything useful.

 

Could you first explain the terminology? Also, is this work for ordinary, standard mathematics?

[lesolee]

Hello! Since I haven't solved any examples using functions in a while, it's hard for me to solve this example. It would be really nice if someone could help me in some way and explain how i works.

 

So we have a parabola, Y= x*x

The slope of the parabola at any point is what? (A)

Having found the slope of the parabola you now want the equation of a line passing through that point but with a slope at 90 degrees to the parabola. (B)

Do you remember the standard equation of a straight line? ©

Think about the above questions before peeking ...

 

 

_________________ Peeking .........

 

A) if y = x*x then dy/dx = 2x (elementary calculus)

B) The tangent slope is dy/dx and the normal to the tangent (the perpendicular) is -dx/dy.

c) Y= mx + c