Slope of a line
The Slope Formula
Wednesday, December 7, 2011
Monday, October 24, 2011
Sunday, August 21, 2011
Mid Point and Distance of a Line Segment
Midpoint of a Line Segment
A Mid point of a segment with endpoint (x1,y1) and (x2,y2) are
((x1+x2)/2, (y1+y2)/2)
Distance Formula
A Mid point of a segment with endpoint (x1,y1) and (x2,y2) are
((x1+x2)/2, (y1+y2)/2)
Distance Formula
Tuesday, August 2, 2011
Math meeting 08-02-2011-fractions, Proportions, inverse relations
Hi,
we talked about direct and inverse proportion.
We also did part of the problems: we will continue to finish it next meeting
This problem set:
1,We review cross multiplication
2, Children seem to forget the concept of the function y=f(x)
Please review
Next meeting:
08-04-2011 Am10:00-12:00
We will continue to finish and correct the problem set
Friday, July 29, 2011
Math meeting 7-28-2011
Hi,
We have reviewed (07-28-2011)
Next math meeting;
08-02-2011 Am 10:00-12:00
We will discuss problem solving strategies
Fraction, direct and inverse fraction
Direct and Inverse Proportion
Two types of proportions
Direct proportion;
Y=f(x)=kx k is a constant
or Y/X=k
Y and X are direct proportion
The more X is, the more Y is
ex: buy one book costs $2, two books costs $4, 3 books costs $6.......
(given k=2, when x=1then y-=2,x=2then y=4 ,x=3 then y=6.............)
the more x is, the more y is
the more the books, the more the cos is
x and y are direct proportion (books and cost are direct proportion)
Inverse proportion:
Y=f(x)=k /X k is a constant
or XY=k
X and Y are inverse proportion
The more X is, The less Y is
ex: D=RT
if D is a constant.
The faster the rate is , the less the time it will take
EX1: k=xy (D=RT) k=xy (D=RT)
Given 120 miles, rate at 30 mph, it takes 4hours(given k=120 120=30x4)
rate at 60 mph, it takes 2 hours(given k=120, 120=60x2)
rate ate 120 mph, it takes 1hour(given k=120 120=120x1)
The more x is, the less y is (k=xy)
The more R is, the less T is (D=RT)
x and y are inverse proportion (R and T are inverse proportion)
Ex2: It takes 10 workers and works 100 hours to finish a project(Given k=1000=10x100 )
It takes 20 workers and works 50 hours to finish a project (k=1000, 1000=20x50)
It takes 40 workers and work 25 hours to finish a project (k=1000, 1000=40x25)
Problem Solving Strategy:
Step1: to recognize if it is direct or inverse proportion
Step2: If it is direct proportion: y=f(x)=kx
If It is inverse proportion: y=f(x)=k/x
Step3: find k=? and put the value in the known variable, and solve the unknown variable.
Q1, For the function f , y=f(x) is inversely proportional to x, when x>0. If f(3) =6, what is the value of f(2)?
Since it is inversely proportional- xy=k, y=k/x
y=f(x)=f(3) =k/3=6, so k=18
f(2)=k/x=18/2=9
Q2, If y is directly proportional to x square and y=1/8 when x=1/2 what is the positive value of x when y=9/2
Since it is directly proportional , y=k(x)(x)
1/8=k(1/4), so k=1/2
9/2=k(x)(x)=1/2(x)(x)
so x=3
Q3, If 5 chickens lay 5 eggs in 5 days. How many eggs will 25 chickens lay in 25 days?
The more chicken, the more eggs, and the less days
Chicken(C) and eggs (E)are direct proportional, and chicken(C) and days(D) are inverse
proportional ,
Therefore, k=CD/E , k=(5x5)/5=5
k=5=(25x25)/D
D= 125
More Study:
Direct proportion;
Y=f(x)=kx k is a constant
or Y/X=k
Y and X are direct proportion
The more X is, the more Y is
ex: buy one book costs $2, two books costs $4, 3 books costs $6.......
(given k=2, when x=1then y-=2,x=2then y=4 ,x=3 then y=6.............)
the more x is, the more y is
the more the books, the more the cos is
x and y are direct proportion (books and cost are direct proportion)
Inverse proportion:
Y=f(x)=k /X k is a constant
or XY=k
X and Y are inverse proportion
The more X is, The less Y is
ex: D=RT
if D is a constant.
The faster the rate is , the less the time it will take
EX1: k=xy (D=RT) k=xy (D=RT)
Given 120 miles, rate at 30 mph, it takes 4hours(given k=120 120=30x4)
rate at 60 mph, it takes 2 hours(given k=120, 120=60x2)
rate ate 120 mph, it takes 1hour(given k=120 120=120x1)
The more x is, the less y is (k=xy)
The more R is, the less T is (D=RT)
x and y are inverse proportion (R and T are inverse proportion)
Ex2: It takes 10 workers and works 100 hours to finish a project(Given k=1000=10x100 )
It takes 20 workers and works 50 hours to finish a project (k=1000, 1000=20x50)
It takes 40 workers and work 25 hours to finish a project (k=1000, 1000=40x25)
Problem Solving Strategy:
Step1: to recognize if it is direct or inverse proportion
Step2: If it is direct proportion: y=f(x)=kx
If It is inverse proportion: y=f(x)=k/x
Step3: find k=? and put the value in the known variable, and solve the unknown variable.
Q1, For the function f , y=f(x) is inversely proportional to x, when x>0. If f(3) =6, what is the value of f(2)?
Since it is inversely proportional- xy=k, y=k/x
y=f(x)=f(3) =k/3=6, so k=18
f(2)=k/x=18/2=9
Q2, If y is directly proportional to x square and y=1/8 when x=1/2 what is the positive value of x when y=9/2
Since it is directly proportional , y=k(x)(x)
1/8=k(1/4), so k=1/2
9/2=k(x)(x)=1/2(x)(x)
so x=3
Q3, If 5 chickens lay 5 eggs in 5 days. How many eggs will 25 chickens lay in 25 days?
The more chicken, the more eggs, and the less days
Chicken(C) and eggs (E)are direct proportional, and chicken(C) and days(D) are inverse
proportional ,
Therefore, k=CD/E , k=(5x5)/5=5
k=5=(25x25)/D
D= 125
More Study:
Math Word Problem of the Day
Tuesday, July 26, 2011
Math meeting 07-26-2011-circle-review
Hi,
We have review properties of a circle we have learned.
I, Vocabularies and definition
http://lin-mathclub.blogspot.com/2011/07/circle-some-definition.html
II, Chords and Circles
http://lin-mathclub.blogspot.com/2011/07/circle-arc-and-chord.html
III, Tangent line
http://lin-mathclub.blogspot.com/2011/07/circle-tangent-line.html
IV, Circle and angles: Central angles and Inscribed angles
http://lin-mathclub.blogspot.com/2011/07/circle-arc-and-chord.html
V, The Alternate Segment Theorem
http://lin-mathclub.blogspot.com/2011/07/alternate-segment-theorem.html
VI, Angles and Circles
http://lin-mathclub.blogspot.com/2011/07/circle-circle-and-angles.html
VII, Chords, Secants, Tangents in Circles-Power of a point
http://lin-mathclub.blogspot.com/2011/07/circle-power-of-point.html
More Study:
Multiple Choice Practice - Circles
Next meeting :
We will discuss Geometry-Quadrilateral Family
We have review properties of a circle we have learned.
I, Vocabularies and definition
http://lin-mathclub.blogspot.com/2011/07/circle-some-definition.html
II, Chords and Circles
http://lin-mathclub.blogspot.com/2011/07/circle-arc-and-chord.html
III, Tangent line
http://lin-mathclub.blogspot.com/2011/07/circle-tangent-line.html
IV, Circle and angles: Central angles and Inscribed angles
http://lin-mathclub.blogspot.com/2011/07/circle-arc-and-chord.html
V, The Alternate Segment Theorem
http://lin-mathclub.blogspot.com/2011/07/alternate-segment-theorem.html
VI, Angles and Circles
http://lin-mathclub.blogspot.com/2011/07/circle-circle-and-angles.html
VII, Chords, Secants, Tangents in Circles-Power of a point
http://lin-mathclub.blogspot.com/2011/07/circle-power-of-point.html
More Study:
Multiple Choice Practice - Circles
Next meeting :
07-28-2011 Am10:00-12:00
We will discuss Geometry-Quadrilateral Family
Monday, July 25, 2011
Math meeting 07-25-2011
Hi,
We discussed circle-power of a point
http://lin-mathclub.blogspot.com/2011/07/circle-power-of-point.html.
Next meeting:
We will review all properties of a circle we have learned
Please print out the attachments and bring to the meeting.
Meeting time:
07-26-2011 Am 10:00-12:00
We discussed circle-power of a point
http://lin-mathclub.blogspot.com/2011/07/circle-power-of-point.html.
Next meeting:
We will review all properties of a circle we have learned
Please print out the attachments and bring to the meeting.
Meeting time:
07-26-2011 Am 10:00-12:00
Saturday, July 23, 2011
Thursday, July 21, 2011
Math meeting 07-21-2011
Hi, We have discussed 1,Circle-angles formed by intersecting chords,secants-tangents-arcs-angle 2, Problem solving : word problems HomeworkAngles in a circle http://www.regentsprep.org/Regents/math/geometry/GP15/PcirclesN2.htmAngles outside a circlehttp://www.regentsprep.org/Regents/math/geometry/GP15/PcirclesN3.htmPractice with circle proofshttp://www.regentsprep.org/Regents/math/geometry/GP15/pracProofs.htmNext Meeting 07-25-2011 10:00-12:00AM Please print the attachments and bring to the meeting |
Tuesday, July 19, 2011
Math meeting 07-19-2011
Hi,
We have discussed the attachment 3-Circle-other angles and circle
Please print out the first two attachments (if you did not print last time)
Next meeting
07-21-2011
10:00am- 12:00
Monday, July 18, 2011
Math meeting 7-18-2011
We have discussed the alternate segment theorem
|
Wednesday, July 13, 2011
Math meeting 7-13-2011
Hi,
Today we have reviewed central and inscribed angles in a circle.
Homework: do the following practice
Ya-Chi
Tuesday, July 12, 2011
Math meeting 7-12-2011
Hi,
We have discussed
1,angles in a circle-central , inscribed angles
2,triangle exterior angle theorem and proportion theorem
Homework:
We have discussed
1,angles in a circle-central , inscribed angles
2,triangle exterior angle theorem and proportion theorem
Homework:
Next meeting:
AM 10:00-12:00 07-13-2011
1, Review:Circle, similar triangle
2, The Alternate Segment Theorem
Monday, July 11, 2011
Meeting time: 7-11-2011
|
Circle-Circle and Angles
Practice Questions
Central angle= 1/2Inscribed angle
More study:
Circles and angles-(Circles: Angles and Arcs )
Thursday, July 7, 2011
Math Meeting : 07-07-2011
Hi,
Today we discuss some vocabularies , chords and arcs about circles
We also review the congruent triangles
Homework:
http://www.regentsprep.org/Regents/math/geometry/GP14/PracCircleChords.htm
Today we discuss some vocabularies , chords and arcs about circles
We also review the congruent triangles
Homework:
http://www.regentsprep.org/Regents/math/geometry/GP14/PracCircleChords.htm
Subscribe to:
Posts (Atom)