Pre-cal 30S 1st Blog

Here's the first blog of the semester:

In class today, we reviewed the stuff we were supposed to learn in Grade 10.. If you forgot.. here it is..

If you are given:
y=2x+15 (which is a straight line, when you draw it on a graph)
the slope is -> m=2/1 (m=rise/run)
just remember to use y=mx+b to help you find the slope which is represented by the letter "m" & y-intercept which is represented by the letter "b"
y-intercept: 15 <- to figure this out just set "x" to 0 ...
y=2(0)+15
y=0+15
y=15
Do the opposite for the x-intercept:
0=2x+15
-15=2x
-15/2=2x/2
x= -15/2
& just so you remember, x-intercepts, zeros & roots are the same thing.. so don't get confused.

So the Domain would be {x׀x € R}which means "x such that, is a member of real numbers"
The Range would be {y׀y € R} which means "y such that, is a member of real numbers"
Writing things such as {y׀y € R} or {x׀x € R} is called using "Set Notation," it pretty much just needs the 2 brackets {} around it to be considered "Set Notation".

Okay, well I can't get the pictures of the parabolas up but I think you guys pretty much know what it is.. it's like a line that curves and when you do the vertical line test it only touches ONE point of the line. The lines go on forever so you should be putting arrows on the ends of these lines.. other wise Mrs. Ingram said we could lose 1/2 marks on tests if we don't. + u should also label the graph for example, show where the "x", "y" is on the graph or you could lose marks for that, too. The general parabola is y= x²

The vertex is where the curve changes its direction, it'll have an "x" and "y" coordinate
The axis of symmetry is the "line" going through the curve the same amount of units or spaces or whatever you call it, from the middle of the curve. It's pretty much the line that separates the parabola from the midpoint or cuts the parabola in half so that both sides would be even. You can find if by setting x = 0

The hw that's due 4 2morrow is Exercise 1: Quadratic Functions, all the questions except # 12