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Mathematics Dictionary
Dr. K. G. Shih

Senior High Mathematics
Study Tips and Home Works
How to do the home work ?

  • 1. Answr the questions first in each home work.
  • 2. Then read the related keywords of the given title in SM.
  • 3. Do the questions again as home work.


  • S01 | - 01. Draw a circle passing three given points.
  • S02 | - 02. Solve x^4 + x^3 + x^2 + x + 1 = 0
  • S03 | - 03. What is ex-central triangle ?
  • S04 | - 04. How to find the 3rd perfect number ?
  • S05 | - 05. Sequence in Pascal triangle : Sum[n*(n+1)/2] = n*(n+1)*(n+2)/3!
  • S06 | - 06. Intersections of y = a*x^2 + b*x + c with its inverse
  • S07 | - 07. Intersections of y = a*x^2 + b*x + c with y = 1/x
  • S08 | - 08. Intersections of y = x^2 - 6*x + 8 with its inverse.
  • S09 | - 09. Properties of numbers by its factors
  • S10 | - 10. Equation of e^x + e^(2*x) + e^y + e^(2*y) = 12
  • S11 | - 11. Pedal triangle of triangle ABC
  • S12 | - 12. Amicable numbers
  • S13 | - 13. Absolute Abs(x^2 - 6*Abs(x) + 8) = n
  • S14 | - 14. Series and sequences
  • S15 | - 15. Solve x^7 +2*x^6 -5*x^5 -13*x^4 -13*x^3 -5*x^2 +2*x +1 = 0
  • S16 | - 16. Solve x^5 - 1 = 0
  • S17 | - 17. Compare ((x-h)/4)^2-((y-k)/4)^2 =1 & ((x-h)/4)^2-((y-k)/4)^2 =-1
  • S18 | - 18. Ortho-center theory
  • S19 | - 19. Transformation matrix of a circle
  • S20 | - 20. Parametric equation : x = sec(t) and y = tan(t)
  • Home Works



    S01. Home Work 1 : Draw a circle passing three given points

    Geometrical method
    Analytic geometric method
    • Study subjects : Find equation of the circle passing three points.
    • Method
      • a. Substitute 3 points into x^2 + y^2 +a*x + b*y + c = 0.
      • b. Solve 3 linear equations of a,b,c.
      • c. Use the completing square to find center and radius.
    Go to Begin

    S02. Home Work 2 : Solve x^4 + x^3 + x^2 + x + 1 = 0 using DeMoivre's theorem

    Questions
    • 1. What is the DeMoivre theorem ?
    • 2. How to solve x^5 - 1 = 0 using DeMoivre's theorem ?
    • 3. Solve x^4 + x^3 + x^2 + x + 1 = 0
      • Prove that cis(72), cis(144), cis(216) and cis(288) are solutions.
      • Prove that cos(72) + cos(144) + cos(216) + cos(288) = -1.
      • Prove that sin(72) + sin(144) + sin(216) + sin(288) = 0.
      • How to use construction method to find solutions ?
    Study subjects : DeMoivre's theorem and application.
    Go to Begin

    S03. Home Work 3 : What is ex-central triangle ?

    Construction
    • 1. Draw a triangle ABC ?
    • 2. Draw three es-centers of triangle ABC.
    • 3. Join the centers J, K, L with vertices of the triangle.
    Questions
    • 1. Prove that J, C, K are colinear.
    • 2. Prove that I is the in-center of triangle ABC.
    • 3. Prove that I is also the orthocenter of triangle JKL.
    • 4. Prove that ABC is pedal triangle of triangle JKL.
    Study subjects : The ex-central triangle.
    Study subjects : The five centers of triangle.
    Go to Begin

    S04. Home Work 4 : How to find 3rd perfect number ?

    • Properties of perfect number.
      • Perfect number = 1^3 + 3^3 + 5^3 + ....
      • Perfect number = (2^(n-1))*(2^n-1).
      • 2^n - 1 is a prime number for a perfect number
    • Third perfect number is between 400 and 500.
    Study subjects : Perfect numbers.

    Go to Begin

    S05. Home Work 5 : Sequence in Pascal triangle

    • 1. What is Pascal triangle ?
    • 2. Prove that Sum[n*(n+1)/2] = n*(n+1)*(n+2)/3!.
    • 3. Prove that Sum[C(n+1,2)] = C(n+2,3). Where C(n,r) is coeff of binomial expansion.
    Study subjects : Sequence and Pascal triangle.

    Go to Begin

    S06. Intersection of y = a*x^2 + b*x + c with its inverse


    Go to Begin

    S07. Intersection of y = a*x^2 + b*x + c with y = 1/x


    Go to Begin

    S08. Estimate intersections of y = x^2 - 6*x + 8 with its inverse.

    Study subjects : Intersections of quadratic function with y = 1/x.
    • Click Start after entering application program.
    • Click subject 6 in upper box.
    • Click program 10 find sketch program.
    • Type in coefficients 1, -6, 8.
    • Estimate the answers from the diagram.

    Go to Begin

    S09. Properties of numbers by its factors

    Find the properties of the number 27, 28, 29 30 by their factros.
    • Find the factors of a given number.
    • Sum the factors of the number exluding number itself.
    • Give the properties of the number (abudunt, deficient, perfect, prime).
    • See Q02 of QA web-page.

    Go to Begin

    S10. Equation : e^x + e^(2*x) + e^y + e^(2*y) = 12

    Home work questions
    • 1. Find equation of tangent when x = ln(3).
    • 2. Find y when x = ln(2).
    • 3. How to sketch the curve of y verse x ?
    Reference

    Go to Begin

    S11. Pedal triangle of triangle ABC

    Home work questions
    • 1. What is pedal triangle of triangle ABC ?
    • 2. Prove that in-center of pedal triangle is also orthocenter of triangle ABC.
    • 3. Prove that vertices A, B, C are es-center of the pedal triangle.
    • 4. Prove that triangle ABC is ex-central triangle of its pedal triangle.
    Reference

    Go to Begin

    S12. Amicable numbers

    Home work questions
    • 1. What are amicable number pairs ?
    • 2. Prove that 220 and 284 are amicable pairs.
    • 3. If 1184 and n are amicable pairs, find n.
    Reference
  • 1. Study subjects : Amicable number pairs
  • 2. Study subjects : Who discover amicable number pairs ?

    Go to Begin

    S13. Absolute operation : Abs(x^2 - 6*Abs(x) + 8) = m

    Home work questions
    • 1. How many real roots Abs(x^2 - 6*Abs(x) + 8) = 0.5 ?
    • 2. How many real roots Abs(x^2 - 6*Abs(x) + 8) = 1 ?
    • 3. How many real roots Abs(x^2 - 6*Abs(x) + 8) = 3 ?
    Reference

    Go to Begin

    S14 : Series

    Questions
    • 1. Prove that Sum[n^2] = n*(n+1)*(2*n)/6.
    • 2. Prove that Sum[n^3] = (n*(n+1)/2)^2.
    • 3. Prove that Sum[n*(n+1)/2] = n*(n+1)*(n+2)/6
    Reference
  • 1. Study subjects : Sequence of 1, 4, 9, 16, ...
  • 2. Study subjects : Sequence of 1, 8, 27, 64, ...
  • 3. Study subjects : Sequence of 1, 3, 6, 10, ....
    Go to Begin

    S15 : Solve equations

    Questions
    • 1. Solve x + 1 = 0
    • 2. Solve x^2 + x + 1 = 0
    • 3. Solve x^4 - 7*x^2 + 1 = 0
    • 4. Change (x+1)*(x^2+x+1)*(x^4 - 7*x^2 + 1) to polynomial form
    • 5. Solve x^7 + 2*x^6 - 5*x^5 - 13*x^4 - 13*x^3 - 5*x^2 + 2*x + 1 = 0
    Reference

    Go to Begin

    S16 : Solve x^n - 1 = 0

    Questions
    • 1. Solve x5 - 1 = 0
      • 1. Use DeMoivre's thereom : x = cis(A) for A = 72, 144, 216, 288, 360
      • 2. Use constructions : Draw unit circle and angle A = 72, 144, 216, ...
      • 3. 1st root r1 = cos(72) + i*sin(72)
      • 4. 2nd root r2 = cos(144) + i*sin(144)
      • 5. 3rd root r3 = cos(216) + i*sin(216)
      • 6. 4th root r4 = cos(288) + i*sin(288)
      • 7. 5th root r5 = cos(360) + i*sin(360) = 1
    • 2. Express (x - 1)*(x^4 + x^3 + x^2 + x + 1) as polynomial form
    • 3. Solve x^4 + x^3 + x^2 + x + 1 = 0
    Reference

    Go to Begin

    S17 : Compare ((x-h)/4)^2-((y-k)/4)^2 =1 & ((x-h)/4)^2-((y-k)/4)^2 =-1

    Compare the following
    • 1. Assymptotes
    • 2. Coordinates of center
    • 3. Coordinates of vertices
    • 4. Coordinates of focus
    • 5. Focal length
    • 6. Equation of Principal axis
    • 7. Equation of directrix
    • 8. Equation in polar form
    Reference

    Go to Begin

    S18 : Ortho-center Theorem

    Ortho-center
    • 1. What is ortho-center of triangle ABC
    • 2. Relation between ortho-center of circum center : Prove that AO : UR = 2 : 1
      • O is ortho-center and U is circum-center
      • AOD perpendicular to AB and UR perpendicular to AB
    • 3. Trinangle ABC has pedal triangle PQR : Prove O is in-center of triangle PQR
    Reference

    Go to Begin

    S19 : Transformation matrix of a circle

    Study transformation of circle (x-h)^2 + (y-k)^2 = r^2
    • Find eqnation and transformation matrix to transform circle as image of y = x
    • Find eqnation and transformation matrix to transform circle as image of y = -x
    • Find eqnation and transformation matrix to transform circle as image of x-axis
    • Find eqnation and transformation matrix to transform circle as image of y-axis
    • Find matrix to transform circle as line section x-axis (Projection on x-axis)
    • Find matrix to transform circle as line section y-axis (Projection on x-axis)
    • Find matrix to transform circle as ellipse (Principal axis paralle to x-axis)
    • Find matrix to transform circle as ellipse (Principal axis paralle to y-axis)
    Reference

    Go to Begin

    S20 : Parametric equation

    Equations
    • 1. Graph of x = sec(t) and y = tan(t)
    • 2. Graph of x = tan(t) and y = sec(t)
    Questions
    • Compare the two graphs in rectangular form
    • compare the two graphs in polar form
    Reference

    Go to Begin

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    Copyright © Dr. K. G. Shih, Nova Scotia, Canada.

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