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Completing The Square
Quadratic Inequalities [Divide negative, flip sign if it’s
Question Type 1 : Quadratic Inequalities Find the range of values of
for which
Step 1: Flush everything to the left and rearrange according to^ 𝑎
Step 2: Simplify and rearrange according to
Step 3: Solve your quadratic inequalities Question Type 2 : Reverse Quadratic Inequalities Find the values of 𝑝^ and 𝑞^ for which
3 or
is the solution set of
Question Type 1: Nature of Roots Find the range of 𝑎, for which the graph is
Step 2: Flush everything to the left and rearrange according to^ 𝑎
Step 3: Determine Nature of Roots base on the condition Step 4: Simplify and rearrange according to
Step 5: Solve your quadratic inequalities Step 6: Reject if Necessary Question Type 2 : Proving Questions (Prove/Show/Explain) Show that the expression is negative for all real values of
Prove that the expression is always positive for all values of
Step 1: Flush everything to the left and rearrange according to
Step 2: Apply
but don’t put the sign Step 3: Simplify and rearrange according to
Step 4: Use Completing The Square/otherwise (See Condition) Step 5: For all real values of 𝑥, ____ is positive/negative (Proven) Example^ 𝑏
Since
and line intersects the curve for all real values of k.
Mensuration with Surds Cone Surface Area:
Volume:
Pyramid Surface Area: Add all sides Volume: 1 Base area x Height 3 Hemi
[open] /
Volume:
Sphere Surface Area:
Volume:
Prism Surface Area: Add all sides Volume: Cross Section x Length Cylinder Surface Area:
Volume:
implies that
𝑥^ and
E.g.
or^
Multiplication : √𝑎^ ×^ √ 𝑏^ = √𝑎𝑏 𝑎^ × √𝑏 =^ 𝑎√𝑏 𝑐√𝑎 ×^ 𝑑√𝑏 =^ 𝑐𝑑√ 𝑎𝑏 𝑎 √ ×^ √ 𝑎^ = 𝑎 𝑏√𝑎 ×^ 𝑏√𝑎 =^ (^2) 𝑏𝑎 Number ×^ N umber, Surd ×^ Surd Division : 𝑎 ට 𝑏 √= (^) 𝑎 √𝑏 Addition & Subtraction : 2 √^3 +^5 √^3 =^7 √^3 4 √ 2 − √^2 =^ 3 √^2 Similar Terms can be Added or subtracted Key To Solving Surds: Simplify all Surds to their simplest forms √^50 =^ 5 √^2 √^27 =^ 3 √^3 Rationalisation of Surds : (We don’t like SqRoots in Denominator) Note: Change Signs while Rationalizing 3 ×^2 √
Step 1:
3 or
Step 2:
0 (Reverse and Form Back Original) Step 3:
(Expand) Step 4:
(Rearrange according to question) Step 5:
1 (Compare coefficient) Determinants (Curve & Axis)^2 𝑏 −^4 𝑎𝑐^ < 0 No Roots No Real Roots or Imaginary Roots or Graph is always positive (Completely above x - axis) or Graph is always negative (Completely below x - axis) (^2) 𝑏− 4 𝑎𝑐 =^0 1 Roots Real & Equal or Real & Repeated Roots (^2) 𝑏− 4 𝑎𝑐
^0 2 Roots
Real & Distinct Roots or Different Roots (^2) 𝑏− 4 𝑎𝑐 ≥^0 1/2 Roots Graph has real roots or Graph Intersects the x - axis
Question Type 1: Solving Unknowns Question Type 2: Remainder & Factor Theorem Question Type 3: Reverse Engineer to get Polynomial Equation Question Type 4: Cubic Factorisation^3 (𝑥
Question Type 5 : Solve Cubic Equations
Question Type 5 (Hence) : Solve Cubic Equations Type 1: Nature of Roots After long division, you can use
to determine the number of roots of the Quadratic Equation. Recap: 𝑏^^2
root 𝑏^^2
roots 𝑏^^2
root If asked for TOTAL roots, remember to add Initial Solutions. Type 2: Replacement Level 1:^3 𝑥
Hence, solve
Level
Hence ,^ solve
Level 3: Hence, Solve
12^ Greetings from Paradigm! Hope this Cheatsheet can help you in your O Levels Preparation. We wish you all the best If you’re looking for more Resources & Study Advice, Simply Scan this QR Code! Method 1: Fully expand and compare coefficient Method 2: Substitution Method Given that the identity^3 𝑥
1 ) + C, for all real values of x, find the value of A, of B and of C by substitution. Step 1: Sub
(to get C) Step 2: Sub
2 (to get B) Step 3: Sub in convenient value of
e.g.
0 (to get A) You will find A, B, and C easily. Step 1: Listing down all the different variations and conditions Step 2: Always check the coefficient of the highest power, unsure put 𝑘 Step 3: Substitution Method and Apply Remainder and Factor Theorem The highest order term of a polynomial 𝑓(𝑥 )^ is 3 𝑥 4.^ Three of the roots of the equation 𝑓(𝑥 )^ = 0 are (^1 0) , 3 and −^1
.^ When 𝑓(𝑥 )^ Is divided by (𝑥^ −^2 ), the remainder is 30. Find the expression for 𝑓( 𝑥)^ in descending powers of 𝑥. ( 𝑓𝑥 )^ = (𝑥 )(^3 𝑥 −^1 )(𝑥 +^ 1 )( 𝑥^ − 𝑎) Sub 𝑥^ = 2 𝑓(^2 )^ = (^2 ) (^5 ) (^3 ) (^2 − 𝑎)^ =^30 60 −^30 𝑎^ = 30 𝑎^ = 1 𝑓(𝑥 )^ = (𝑥 )(^3 𝑥 −^1 )(𝑥 +^ 1 )( 𝑥^ − 1 ) 𝑓(𝑥 )^ = 3 𝑥 4 − (^3) 𝑥 −^3 (^2) 𝑥 +^ 𝑥 Solve the cubic expression
9 completely. Use Mode
(Don’t Write This) Substitute
By^ Factor Theorem
1 )^ is a factor. Using Long Division ,^ (Show Working) You will get
9 as the Quotient. Use Mode
Sub
Note: If Mode 3,3 shows i maginary number, use (^2) 𝑏 −^4 𝑎𝑐^ and show it is <^0 . *Look at the question. They may ask you to express answers in surd forms.^ Apply Quadratic Formula and simplify. 𝑥^ = −𝑏 ±^ √ (^2) 𝑏− 4 𝑎𝑐 2 𝑎 Important terms
Coefficient of a Variable: Number in front of the variable (algebra) 2 is the coefficient of
is the coefficient od
2 Degree of a Polynomial: The degree of a polynomial is the highest power in the equation Adding, Subtraction & Multiplication follows algebra rules Division of Polynomials Note: When you encounter polynomials such as Divide
by
Please write it as
Fil up the missing terms with
Step 1: Mode 3 ,^4 to find the factor Step 2: Choose the smallest solution and prove that it is a Factor Step 3: Write by Factor Theorem (𝑥^ −^ 𝑎 )^ is a factor Step 4: Conduct Long division to obtain your quotient Step 5: Using your quotient, apply quadratic equation to get your roots Step 6: If roots are irrational, use (^2) 𝑏 −^4 𝑎𝑐^ and show it is <^
Step7: Souble check all answers with Mode 3 ,^4
Step 1: If improper fraction and Conduct Long Division Improper = Degree of numerator
Degree of denominator Dividend^ Divisor
Quotient
Remainder^ Divisor Step 2: Ensure Denominator is Fully Factorised Step 3: Apply Partial Fraction Rules Step 4: Eliminate all fractions by multiplying the Denominator Step 5: Solve using Substitution Method Express 4 − 4 𝑥− (^28) 𝑥 (^2) 𝑥(𝑥 +^2 ) as a sum of its partial fractions. 4 −
2 Let
Let
Let
4 −^4 𝑥− (^28) 𝑥 (^2) 𝑥( 𝑥+ 2 )^
(^2 2) 𝑥
(^5) 𝑥+
Question Type 1: Binomial Expansion Hence Expansion Type 1: Selective Expansion You selectively rainbow the terms to obtain the algebra you need. Hence Expansion Type 2: Full Expansion You have no choice but to expand everything fully Hence Replacement Type 1: Number (𝟐𝒙
𝟐𝟗 𝟐^
𝟏𝟐𝟏 𝟒
𝟐𝟕𝟓^ 𝟖^
Observe that x is replaced with 0.1. 𝟑.^ 𝟐
𝟏𝟏^
Hence Replacement Type 2: Algebra (𝟏^
Question Type 2: Finding Specific Term^ Question Type 3: When
is unknown Timeline to O Levels Jun
-^ Complete Topical Revision (TYS) & Notes Jul^ -^ Kickstart Prelim Papers Aug -^ Prepare for Prelims Sep -^ Complete Yearly TYS + Prelim Papers Oct -^ Final Revision. Ready to ACE O’s! Towards Os, I will be sharing in - depth on - MUST Know Questions for Os - AM Paper 2 Analysis See you inside! Case Fraction N(𝑥) D(𝑥) Form of denominator, D(𝑥 ) Partial Fraction Form (where A, B and C are^ unknown constants) 1 N(x ) (ax^ +^ b) (cx^ +^ d) Linear Factors A ax +^ b +^ B cx +^ d 2 N(x ) (ax^ +^ b (^2) ) Repeated Linear Factors A ax +^ b +^ B (ax^ +^ b) 2 N(x ) (ax^ +^ b) (cx^ +^ d) 2 Linear and Repeated^ Linear Factors A ax +^ b +^ B cx +^ d +^ C (cx^ +^ d (^2) ) 3 N(x ) (ax^ +^ b (^2) )(x +^ c 2 ) Linear and Quadratic^ (which cannot be^ factorised) Factors A ax +^ b Bx+ (^) +^ C (^2 2) x+^ c
General Term Formula:
means
𝑟 When n^ is^ unknown
𝑛(𝑛 −^1 ) 2!^ , where
𝑛(𝑛 −^1 ) (𝑛− 2 ) 3!^ , where
𝑛(𝑛 −^1 ) (𝑛− 2 )(𝑛 −^3 ) 4!^ , where
& so on… Last but not least,
You can use either 1. Binomial Expansion Method or 2. Finding Specific Term Method (𝑎^
=^ ( 𝑛)^ ( 0 𝑛𝑎) −^0 ( (^0) 𝑏) +^ ( 𝑛)^ ( 1 𝑛𝑎) −^1 ( (^1) 𝑏) +^ ( 𝑛)^2 (𝑎) 𝑛−^2 (𝑏) 2 + ⋯^ +^ ( 𝑛)^ ( 𝑛 (^0) 𝑎) 𝑛(𝑏) Note:
)^ can be written as
𝑟 Evaluate
)^ using calculator: Press 3 , Shift
10
𝑥𝑎 𝑦
𝑟
Powers, Special Logs etc) Remember that we can convert integers back into Logarithm as well. For us to do that, we must determine what base we want to change If we want base 5,
log
log
log
Solving Question Type 1: Log to Ind ices Form log
Usually this is in the form of 𝑥^ =
log
Solving Question Type 2: CCC (Change, Combine, Cancel) log
+^ log
=^ log
log
log
3 or
(Reject)
4 log
log
log
log
log
(^4) log𝑥^5
Substitute
log
4 or
log
4 or log
or^
1 5
log
,^ where 𝑎^ >
log
,^ where 𝑎^ >
log
,^ where 0 <
Solving Type 1: Compare Power^5
Solving Type 2: Use Log/Ln to solve
Advance Type 2: Split & Rearrange Solve
𝑥+^3
−𝑥 2 𝑥 4
𝑥^
343 64 𝑥 16
𝑥lg
(^343) lg 64 𝑥 16
343 64
lg 343 64 ÷^ lg 𝑥 16
64
34364
d.^ p.^ ) 112
343 64 Solving Type 3: Substitution^ (
ln^
ln(
log
Restrictions on logarithms: For log
E.g. Show that the equation log
log
has no real solutions: log
4 𝑥−
4 𝑥−
When
, both log
log
are undefined. ∴^ the equation has no real solns.
1.^ Change Base 2.^ Substitute 3.^ Solve
𝑛^ 𝑑𝑦 𝑑𝑥^
𝑛−^1
Chain Rule
𝑑𝑦 𝑑𝑥^
Pro duct Rule:
𝑑𝑦 𝑑𝑥^
𝑑𝑦 𝑑𝑥^
𝑑𝑢 𝑑𝑥 Quotient Rule:
𝑢 𝑣
𝑑𝑢𝑣− 𝑑𝑣 𝑑𝑣𝑢 𝑑𝑥 (^2) 𝑣
Rule: Differentiate Trigo, X^ Angle 𝑑൛sin 𝑑𝑥^ ൣ 𝑓(𝑥 )൧ൟ^ =^ cos [൫𝑓 (𝑥) ൧.^ 𝑓 ′(𝑥) 𝑑൛cos 𝑑𝑥^ ൣ 𝑓( 𝑥)൧ ൟ^ = −^ sin ൣ 𝑓( 𝑥)൧
.^ 𝑓′( 𝑥) 𝑑൛tan 𝑑𝑥^ ൣ 𝑓( 𝑥)൧ ൟ^ = sec 2 ൣ𝑓 (𝑥) ൧.^ 𝑓′ (𝑥) Remember Power, Trigonometry, Bracket 𝑦^ = 𝑠𝑖𝑛 𝑛(𝑓 (𝑥) )^ 𝑑𝑦= 𝑑𝑥^ 𝑛.^ sin 𝑛−^1 (ൣ𝑓 )𝑥൧ ∗^ cos (ൣ 𝑓 )𝑥൧^ ∗^ 𝑓 ′(𝑥) 𝑦^ = 𝑐𝑜𝑠 𝑛(𝑓 (𝑥) )^ 𝑑𝑦= 𝑑𝑥^ 𝑛.^ cos 𝑛−^1 (ൣ𝑓 )𝑥൧ ∗^ − sin (ൣ 𝑓𝑥 )൧^ ∗ 𝑓′( 𝑥) 𝑦^ = 𝑡𝑎𝑛 𝑛(𝑓 (𝑥) )^ 𝑑𝑦= 𝑑𝑥^ 𝑛.^ tan 𝑛−^1 ൣ𝑓( 𝑥)൧ ∗^ sec 2 ൣ𝑓 (𝑥) ൧^ ∗^ 𝑓 ′(𝑥)
[Differentiate Power, Multiply Original Eq] 𝑑ൣ 𝑑𝑥^
𝑓(𝑥
Advance: Law of Indices Logarithm: [Differentiate Bracket, Over Bracket] 𝑑൛𝑎𝑙𝑛 𝑑𝑥^ (ൣ 𝑓 )𝑥൧ ൟ^ = 𝑎^ ( 𝑓′(𝑥 ) 𝑓(𝑥) ) Advance: Law of Logarithm
1 𝐺𝑟𝑎𝑑𝑖𝑒𝑛𝑡 𝑜𝑓 𝑇𝑎𝑛𝑔𝑒𝑛𝑡
𝑑𝑦 𝑑𝑥
𝑑𝑦 𝑑𝑥
(^2) 𝑑
concept in Quadratic Inequality to find Range
Dissect Fraction/Term and explain individually. e.g. Since (^12) (𝑥+^3 )
(^22) (𝑥+^3 )
𝑑𝑦 𝑑𝑡
3 x the Rate of Change of Y)
(^2) dy dx
(^2) d
2 y^2 dx
Cone Surface Area:
Volume:
Pyramid Surface Area: Add all sides Volume: 1 Base area x Height 3 Hemi
[open] /
Volume:
Sphere Surface Area:
Volume:
Prism Surface Area: Add all sides Volume: Cross Section x Length Cylinder Surface Area: 2
Volume:
[Power +1. Divide New Power] ∫^ 𝑝𝑥
𝑛+^1 𝑛^ +
Definite Integrals (Upper Limit
-^ Lower Limit) ∫^
𝑏 𝑎^
𝑛𝑝𝑥
𝑛𝑝𝑏
Algebra :^ [Power +1, Divide New Power, Divide Coeff
+^1 (𝑛^
𝑞𝑥+
𝑞𝑥+ 𝑟 𝑞^
2 𝑥+ 𝑥𝑒𝑥 (^) 𝑒
2 𝑥^
Note: You can only integrate
,^ sec
.^ Any other Trigo needs to be converted.
[Double Angle]
[Double Angle]
1 ln 𝑝^
Note: Ln integration happens only when denominator is Linear. Ensure that numerator is the coefficient of 𝑥^ in the denominator.
𝟏 𝟐^ 𝒙
𝑑𝑣 𝑑𝑡^
Start ing Position (START) Substitute
0 and
0 (*Origin)
2.^ Turn (TURN) Substitute
, find 𝑡, find
3.^ Final Position (STOP) Use 𝑡, find
ℎ^ and
ℎ^ second. Note: If there are 2 particles colliding, displacement by both particles should be same as point of collision.