All SAT II Math I Resources
Example Questions
Example Question #2 : Transformation
The graphs of and are shown above. Which equation best describes the relationship between and ?
Example Question #221 : Coordinate Geometry
If the point (6, 7) is reflected over the line and then over the x-axis, what is the resulting coordinate?
(–6, –7)
(7, 6)
(6, 7)
(7, –6)
(6, –7)
(7, –6)
A reflection over the line involves a switching of the coordinates to get us (7, 6). A reflection over the x-axis involves a negation of the y-coordinate. Thus the resulting point is (7, –6).
Example Question #683 : Sat Mathematics
You are looking at a map of your town and your house is located at the coordinate (0,0). Your school is located at the point (3,4). If each coordinate distance is 1.3 miles, how far away is your school?
The coordinate length between you and your school is equivalent to the hypotenuse of a right triangle with sides of 3 and 4 units:
The distance is 5 coordinate lengths, and each coordinate length corresponds to 1.3 miles of distance, so
Example Question #13 : Transformations
Line m passes through the points (–4, 3) and (2, –6). If line q is generated by reflecting m across the line y = x, then which of the following represents the equation of q?
2x + 3y = 6
3x + 2y = 18
3x + 2y = 6
2x + 3y = –6
–2x + 3y = 6
2x + 3y = –6
When a point is reflected across the line y = x, the x and y coordinates are switched. In other words, the point (a, b) reflected across the line y = x would be (b, a).
Thus, if line m is reflected across the line y = x, the points that it passes through will be reflected across the line y = x. As a result, since m passes through (–4, 3) and (2, –6), when m is reflected across y = x, the points it will pass through become (3, –4) and (–6, 2).
Because line q is a reflection of line m across y = x, q must pass through the points (3, –4) and (–6, 2). We know two points on q, so if we determine the slope of q, we can then use the point-slope formula to find the equation of q.
First, let's find the slope between (3, –4) and (–6, 2) using the formula for slope between the points (x1, y1) and (x2, y2).
slope = (2 – (–4))/(–6 –3)
= 6/–9 = –2/3
Next, we can use the point-slope formula to find the equation for q.
y – y1 = slope(x – x1)
y – 2 = (–2/3)(x – (–6))
Multiply both sides by 3.
3(y – 2) = –2(x + 6)
3y – 6 = –2x – 12
Add 2x to both sides.
2x + 3y – 6 = –12
Add six to both sides.
2x + 3y = –6
The answer is 2x + 3y = –6.
Example Question #222 : Coordinate Geometry
Explain in words the transformations from the parent function
for below.
Reflection over the x-axis, vertical stretch by a factor of 2, translate left 5 spaces and up 4 spaces.
Reflection over the y-axis, horizontal stretch by a factor of 2, translate left 5 spaces and up 4 spaces.
Reflection over the y-axis, vertical stretch by a factor of 2, translate right 5 spaces and up 4 spaces.
Reflection over the x-axis, vertical stretch by a factor of 2, translate right 5 spaces and up 4 spaces.
Reflection over the x-axis, vertical stretch by a factor of 2, translate right 5 spaces and up 4 spaces.
This quadratic is presented in vertex form.
First, the negative sign will reflect the graph over the x-axis, if the negative sign were inside the parentheses it would be reflected over the y-axis.
Second, the 2 will stretch the graph vertically, if the 2 had been inside the parentheses that would have been a horizontal shrink.
Third, the 5 inside the parentheses, translates the graph 5 spaces right because we are plugging in a positive 5 into the original vertex form for "h". A negative 5 would change the sign inside the parentheses.
Finally, the 4 outside the parentheses is the k-value, which translates the graph up 4 spaces in this case.
Example Question #462 : Advanced Geometry
If , what would be if it is equivalent to reflected over the x-axis.
If the function is reflected over the x-axis, then .
It will be the opposite of what is currently written.
Therefore,
becomes
.
Example Question #12 : Transformation
What would become if it was reflected over the y-axis to become ?
When a function is reflected over the y-axis, .
becomes
which is simplifed as
.
Example Question #3 : Transformation
Let f(x) = x3 – 2x2 + x +4. If g(x) is obtained by reflecting f(x) across the y-axis, then which of the following is equal to g(x)?
x3 + 2x2 + x + 4
–x3 + 2x2 – x + 4
–x3 – 2x2 – x + 4
–x3 – 2x2 – x – 4
x3 – 2x2 – x + 4
–x3 – 2x2 – x + 4
In order to reflect a function across the y-axis, all of the x-coordinates of every point on that function must be multiplied by negative one. However, the y-values of each point on the function will not change. Thus, we can represent the reflection of f(x) across the y-axis as f(-x). The figure below shows a generic function (not f(x) given in the problem) that has been reflected across the y-axis, in order to offer a better visual understanding.
Therefore, g(x) = f(–x).
f(x) = x3 – 2x2 + x – 4
g(x) = f(–x) = (–x)3 – 2(–x)2 + (–x) + 4
g(x) = (–1)3x3 –2(–1)2x2 – x + 4
g(x) = –x3 –2x2 –x + 4.
The answer is –x3 –2x2 –x + 4.
Example Question #21 : Transformations
What is the period of the function?
1
π
4π
3π
2π
4π
The period is the time it takes for the graph to complete one cycle.
In this particular case we have a sine curve that starts at 0 and completes one cycle when it reaches .
Therefore, the period is
Example Question #22 : How To Find Transformation For An Analytic Geometry Equation
Assume we have a triangle, , with the following vertices:
, , and
If were reflected across the line , what would be the coordinates of the new vertices?
When we reflect a point across the line, , we swap the x- and y-coordinates; therefore, in each point, we will switch the x and y-coordinates:
becomes ,
becomes , and
becomes .
The correct answer is the following:
The other answer choices are incorrect because we only use the negatives of the coordinate points if we are flipping across either the x- or y-axis.