# How do you find the equations for the normal line to #x^2+y^2=20# through (2,4)?

##### 2 Answers

Apr 23, 2017

#### Explanation:

:)))

Apr 23, 2017

The equation is

#### Explanation:

The derivative of this relation is given by

#2x + 2y(dy/dx) = 0#

#2y(dy/dx) = -2x#

#dy/dx= -x/y#

The slope of the tangent line is

#m_"tangent" = -2/4 = -1/2#

Therefore, the slope of the normal line is

#y - 4 = 2(x - 2)#

#y- 4= 2x - 4#

#y = 2x# , as obtained in the other answer

Hopefully this helps!