Tips Flashcards

(60 cards)

1
Q

For a given annual % of interest & initial principal

A

Increasing the frequency of compounding, increases the interest amount accumulated

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2
Q

If multiply/divide both sides of an inequality with a -ve number

A

DIRECTION of the inequality changes (reverses)

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3
Q

Listing down factors of a number

A

Use the T method (stop when pairs start repeating)

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4
Q

Multiple of every +ve integer

A

0

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5
Q

Standard form for a Quadratic equation

A

y=ax²+bx+c; if |a| > 1 skinny, if |a| < 1 wide; if a>0, graph opens upwards, if a<0, graph opens downwards

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6
Q

Impact of outliers on Median

A

Changing highest/lowest no on a list, DOESN’T change median

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7
Q

When there is a distinct outlier or a set of outliers in one direction

A

That pulls the mean away from the median

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8
Q

Exponents of prime factors of a square

A

Must all be EVEN

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9
Q

Numbers with exactly 3 divisors

A

Squares of prime numbers (1, p, p²)

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10
Q

Numbers with 5 factors can be

A

Square of a prime’s square (1, p, p², p³, p⁴)

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11
Q

Some mathematical exceptions (x, x²)

A

For most +ve nos, x² > x; For x=0 & x=1, x²=x; For fractions b/w 0 & 1, x²<x

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12
Q

If divisor > dividend, q=?, r=?

A

q=0, r=dividend

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13
Q

Squaring both sides of an inequality

A

If both sides are +ve, then can square; If opp. signs, then can’t square

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14
Q

Adding mean term to a list, shifts standard deviation

A

to LOWER value

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15
Q

LCM & HCF

A

LCM=product of HIGHEST powers; HCF=product of LOWEST powers

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16
Q

Perfect squares

A

The only integers with an ODD number of factors

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17
Q

Numbers with 4 factors can be

A

Product of 2 prime numbers (1, p, q, pxq) / Cube of a prime number (1, p, p². p³)

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18
Q

Always +ve

A

Factors of a +ve integer/ Remainders/ Prime numbers

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19
Q

Always integers

A

Multiples of a +ve integer / Odd & even numbers

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20
Q

[Exception] Quadratics have 2 solutions

A

(a-b)² = 0 & (a+b)² = 0 Yield only 1 solution

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21
Q

A set of ‘n’ consecutive inegers will always contain one no.

A

Divisible by n (if n is odd, sum of n consecutive integers will be divisible by n)

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22
Q

a⁰ = ?

A

1 (for all a except 0, i.e., 0⁰ = undefined)

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23
Q

Addition with mod

A

|x+y| <= |x| + |y| (equal when x,y have same sign)

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24
Q

Subraction with mod

A

|x-y| => |x| - |y| (equal when x,y have same sign & |x| >= |y|

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25
Impact of outliers on Mean
Changing highest/lowest no on a list, CHANGES mean
26
Mutually exclusive events
2 events canNOT occur at the same time
27
Independent events
One event remains UNAFFECTED by the occurence of the other event
28
Data set values x -> ax+b, μ=? σ=?
a -> aμ + b; σ -> aσ
29
If xᵃ = 1
then a=0 & x = any number (or) a = any number & x=1
30
Data set that is symmetric about its average
Average = Average(least, greatest)
31
Terminating decimal depends on
Factors other than 2 & 5 (i.e., fractions with 2s and 5s terminate, while others recur)
32
Consecutive multiples of same number
μ = Median
33
Consecutive integers
μ = Median
34
Evenly spaced numbers / Any arithmetic sequence
μ = Median
35
Symmetrical list
μ = Median
36
If 2 series of consecutive multiples of 'p' have the same middle no
then the 2 series have the same μ
37
If 2 series of consecutive multiples of 'p' have the same no of terms
then the 2 series have the same σ
38
If |a| = b then
a = b (or) a = -b
39
Even roots of
positive numbers -> +ve output; -ve numbers -> doesn't apply
40
If (x+y) is divisible by d & x is divisible by d
y is divisible by d
41
aˣ = ?
Every prime factor within the prime factorisation of that integer MUST have a power of x/its multiples
42
Atleast 1 even factor in a product => product will be...
EVEN
43
Fractions s ⁄ p & s ⁄ q where p>q [Bigger Dr make...]
s ⁄ p < s ⁄ q [...Smaller fractions]
44
If x & y are each divisible by d
then (x+y) is divisible by d
45
Fraction a/b; Adding p&q (a+p)/(b+q); result?
(a+p)/(b+q) will be closer to p/q than a/b; If a/b < p/q => a/b < resultant; If a/b > p/q => a/b > resultant
46
[Exception] We need N equations to solve for N variables
Equations must be independent to count as separate / Cancellation of several variables at once helps
47
Odd roots of
positive numbers -> +ve output; negative numbers -> -ve output
48
x is what % of y
x/y * 100
49
x is what % > or < y
(x/y - 1)*100 or (y/x - 1)*100
50
If more than half the numbers in a list have the same value (x), median=?
x (regardless of values of remaining numbers)
51
Product can be ODD if and only if
Every single factor is ODD
52
Units digit of any product will be influenced by
ONLY the units digits of the 2 factors
53
If Nr increases & Dr decreases, fraction?
Fraction increases
54
p is a factor of q
q = kp
55
q is a multiple of p
q = kp
56
Inequality/Equality of type x-y & y-x on two sides
Unless x & y are equal +ve on one side & -ve on the other (opp signs)
57
When a perfect square ends with an even number of zeros, the square root of such a perfect square will have exactly ___ of the number of zeros to the right of the final nonzero digit as the perfect square.
half
58
If a decimal with a finite number of decimal places is a perfect square, its square root will have exactly ___ of the number of decimal places. Thus, a perfect square decimal must have an ___ number of decimal places.
Half, Even
59
If two absolute values are equal, it must be true that the expressions within the absolute value bars are either
equals or opposites
60
If x² < |x| and x≠0, the range of x is
-1 < x < 1