Fall 2016 SAT dates

The next dates for the SAT in Seattle are Oct.1, Nov. 5, and Dec. 3. Make sure to give yourself ample time to prepare and take the test multiple times. Registration deadlines are Sept. 1, Oct. 7. and Nov. 3, respectively. More info at the College Board .
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Period of Trig Functions

Let's start with the general equations of: Y=A sin (B(x-c))+D In this post, we'll talk about the B term. This term helps us find the period, the distance required to complete one cycle. It multiplies the angle. For example y=sin(90°) or in radians, y=sin (π/2) is 1. But if you make B=2 instead of 1 (not shown but assumed in the previous equation), it now looks like y=sin(2(90°) which simplifies to y=sin(2(180°). Or in radians, y=sin(2(π/2)) which simplifies to y=sin(π). These now equal...
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One to one functions

In algebra 1 and algebra 2, the topic of one to one functions often comes up. We know that if a function is one to one, it has an inverse, which can be useful knowledge. Graphical approaches: Use horizontal and vertical line tests. Draw a vertical line through the graph and it should only intersect with function at one point. Draw a horizontal line through the graph and it should only intersect at one point. example of a function that is not one to one (fails horizontal line test): e...
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Trig functions: Amplitude

Our basic y=sin (x) function looks like this, with the y axis coming in increments of 1 and the x axis coming in increments of π . Now, what happens if the coefficient of sin(x) is changed from 1 (assumed but not written) to -1?   Here's a gif of it... all the y-coordinates are now negative where they were previously positive in y=sin(x). And for y=sin(x) all y coordinates which were negative are now positive.   If we looks at a function such a...
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Graphing trigonometric functions

Trigonometric functions begin with a review of the unit circle and trig ratios. Y=sin(x) begins at the origin, peaks y=1, crosses the x-axis at pi, bottoms out at y=-1 and ends its first period at 2pi,0. Y=cos(x) starts at y=1, descends to cross the x-axis at pi/2, bottoms out at y=-1, crosses the x-axis at 3pi/2, and finishes its period at 2pi. Now, for all functions F(t)=A(Bt-C) + D where f(t) is a trig function, we know that: A: amplitude, B:period=2pi/|B|, C: phase shift is C/B...
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Converting radians to degrees

What are radians?
Most students in Algebra II are comfortable using degrees, as that was typically included in their previous geometry course. Radians are an alternative way to measure angles and their refer to the length of the arc on the unit circle for a given angle. For example, a 45 degree angle corresponds to π/4 radians. Think of it like this: the circumference of a circle is 2πr and with a unit circle having a radius of 1, the circumference is 2π. Thus, a circle has 360 degrees or 2πr. Now, an 1/8 of ...
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The Socratic Method

Parents often ask: What's your approach to tutoring algebra or any math subject? Having volunteered and worked as a tutor for several organizations, I use a combination of training and experience to guide my approach. Generally, I use the Socratic Method. Sometimes student simply want answers to questions but this usually isn't helpful in fostering critical thinking and understanding. If they rely on my help for everything I can't prepare them for independent learning. I ask my students qu...
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Inverse logs: Part II

Let's look at finding the inverse of y=log(x) algebraically. First, recall that y=log(x) is shorthand for y=log10(x). Step 1: Swap x and y. Now we have x=log10(y). Step 2: Transform the log equation into exponential form. 10x=y Step 3: Replace y with the inverse notation of f-1(x). Thus, f-1(x)=10x Try a more challenging one on your own, such as f(x)=log2(x+3)
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Inverse Functions: Part 1

Algebra 2 typically involves the study of inverse functions, among other topics. If you take a function and reflect it over the line y=x, you have its inverse. Let's take y= log(x): Now, let's add the line y=x and the inverse of y=log(x), which is y=10x. We can now see the reflection over y=x: To graph inverse functions you may simply take all the points (x,y) of the original function and swap the x coordinates for the y coordinates. For y=log(x), you can see the first two coordina...
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