Equations of normals
Question
Example:
What is the equation
of the normal to
y  4 x 2  6 x at the
point where x  2 ?
What is the equation
of the normal to
y  3x5  2 x 2 at the
point where x  1 ?
What is the equation
of the normal to
y  2 x  x3 at the
point where x  1 ?
What is the equation
of the normal to
y  5x 2  2 x  25 at
the point where
x  2?
dy
dx
dy
 8x  6
dx
Value of
dy
dx
dy
 16  6  10
dx
Value of m
m
1
1

10 10
What are x1 and
y1 ?
x1  2
y1  4   2   6  2  4
2
Substitute
into
y  y1  m  x  x1 
y4
1
 x  2
10
Rearrange
into the form
ax  by  c  0
10 y  40  x  2
x  10 y  42  0