Linear relationships & numbers
True or False:
-a6=(-a)6
False
-a6=-(axaxaxaxaxa)
(-a)6=(-a)x(-a)x(-a)x(-a)x(-a)x(-a)
If the height of a person is larger, the shoe side of the person is usually larger.
Thus, the height and the shoe suede is _______ (positively/non/negatively) correlated.
positive
Name 4 transformation types we’ve learned.
Answer the question:
(1) Does a correlation coefficient imply the causation relationship(因果關係)?
(2) [True or False] If the correlation coefficient is strong, we can conclude that the line-of-best-fit is reliable in predicting data.
If the scale factor of two similar triangles is 5, what’s the ratio of there areas?
1:25
If the scale factor of two similar pyramids is 3, what’s the ratio of their surface areas? What’s the ratio of their volumes?
surface area 1:9
volume 1:27
Simplify the radical number:
(√6)x(√15)
3√10
Which one represent the data that most frequently occurs?
(A) mean
(B) mode
(C) median
(B)mode
Name 3 similarity postulates for triangles and explain what they mean.
AA, SSS, SAS
What is the ratio of three sides for a 30-60-90 triangle?
1: √3:2
What is the fonts Chelsie usually use for our math materials?
1. Arial
2. Helvetica
3. Century Gothic
4. Times New Roman
4. Times New Roman
What’s the geometry relationship of the two lines? How many solution(s) are there in this linear system?
3x-6y=0
y=0.5x+7
Parallel, 0 solution
Line1: 3x-6y=0, 6y=3x, y=0.5x
Line2: y=0.5x+7
If the correlation coefficient is -0.1, the correlation is (positive/negative/non) and (strong/median/weak).
negative, weak
Which set of angles are not equal to each other? What is the relationship between this set of angles?
(A) consecutive interior angles
(B) vertical angles
(C) alternate interior angles
(D) corresponding angles
(C), they are supplementary (add up to be 180 degrees)
State the definitions of sin, cos, and tan.
Which trigonometry of the angle between a line and x-axis is exactly the slope?
sin=O/H
cos=A/H
tan=O/H
tan of the mentioned angle is the definition of the slope of a line.
Which color is used to represent formative exams on the grade book on ManageBac?
Orange
Which line is the steepest (disregarding the direction)?
(A) 5x+y=4
(B) 5x-2y=4
(C) y-3=3(x+2)
(D)0.5(y-3)=-3(x+2)
The answer is (D)
(A) 5x+y=4; y=-5x+4, slope=-5
(B) 5x-2y=4; 2y=5x-4; y=2.5x-2, slope=2.5
(C) y-3=3(x+2), slope=3
(D)0.5(y-3)=-3(x+2); y-3=-6(x+2), slope=-6
The range of correlation coefficient is between ___ and ___.If the correlation coefficient is larger than ___, it’s a positive correlation; if the correlation coefficient is less than ___, it’s a positive correlation.
-1, 1, 0, 0
What is the image-point if reflect (2,-5) over y-axis?
(-2, -5)
State the value of the trigonometry:
1. sin(45)
2. cos(60)
3. tan(45)
sin(45)=1/√2
cos(60)=1/2
tan(45)=1
In our first summative exam, what kind of stuff is NOT asked to analyze?
(A) a shoe cabinet near a gate
(B) diamond crossing of rails
(C) a bubble tea cup
(D) images of a mirror in a ballet studio
(E) the slope to a basement
(F) some distances about a pond
(G) the water pressure in a plastic bottle
(H) a round cookie box
(A) (C) (E) (G) (H)
(2x-y)2+|3x+y-5|=0
Find x and y
x=1, y=2
(2x-y)2>0 or =0,
Also, |3x+y-5|>0 or =0
If they add up to be 0, then both of the expressions are 0.
Answer the questions:
(1) Does a correlation coefficient imply the causation relationship(因果關係) between the bivariate data?
(2) [True or False] If the correlation coefficient is strong, we can conclude that the line-of-best-fit is reliable on predicting data.
(1) No. It could be a causation relationship, but sometimes it is not this kind of relationship.
(2) Yes
Which transformation is it?
(x,y) -> (−y,x)
Rotate about (0, 0) 90 degrees counter clockwise
The side length of an equilateral triangle is a. Which one can NOT represent the area of this triangle?
(A) a x ax (√3)/2 x(1/2)
(B) a x a x(√3)/4
(C) 0.5 x a x a x cos(60)
(D) 0.5 x a x a x sin(60)
(C)
Explain how to analyze the volume, surface area and the net of a cone.
(Please show on the blackboard)