- #1

Karol

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## Homework Statement

What is the equation of a straight line passing through (1,2) and normal to ##~x^2=4y##

## Homework Equations

Slopes of perpendicular lines:

$$m_2=-\frac{1}{m_1}$$

## The Attempt at a Solution

$$x^2=4y~\rightarrow~m_1=y'=\frac{x}{2}$$

$$m_2=-\frac{2}{x}$$

$$2=-\frac{2}{1}+b~\rightarrow~b=4$$

The equation of the line: ##~y=-2x+4##

The answer should be ##~x+y=3##