EF-122- Square root functions

Alison Campbell
Square root functions

You cannot take the square root of a negative number as it will be an imaginary number.

When dealing with square root equations you have to think of the problem as two separate equations, other wise it will not be an equation, due to the vertical line rule. The vertical line rule tells us that we cannot have a line graphed that a vertical line would go through twice. Therefore you have to treat it as two equations.

When it is y= √(x-4) the x- intercept is 4, when it is y=√(x+4) the x intercept is -4. This is because to find the x-intercept of a line you solve the equation for y=0. See Greg’s post on intercepts for more info on finding x and y intercepts.

When you divide a square root, the slope of the line will flatten out towards the x-axis.

The graph looks like half a parabola, turned 90 degrees

Regular problem:
y= √(4x2) Solve for x
y2= +/-4x2 To get ride of the square root you square both sides and add +/-
y=+/- 2x Simplify and get ride of the squares
x=y/2 Get ride of the 2x by dividing both sides by 2

EF-122:
y=√x+4 Solve for x intercept
0=√x+4 set y to 0
0=√-4+4 find the number that will make the right side 0
x= -4

y=√0+4 Solve for y intercept
y=√4 set x to 0
y= +/-2 Simplify and get ride of the square root