AIEEE Mathematics Quick Review COMPLEX NUMBERS AND DEMOIVRES THEOREM 1. General form of Complex numbers x + iy where x is Real part and y is Imaginary part. 2. Sum of nth root of unity is zero 3. Product of nth root of unity (–1)n–1 4. Cube roots of unity are 1, ω, ω2 5. 1 + ω + ω2 = 0, ω3 = 1, −1 + 3i 2 − 1− 3i ω= ,ω = 2 2
of z represents Ellipse and if k < z1 − z2
x > 0, y > 0
S
x+a x−a +i , a − ib 2 2
nπ 4
a 2 + b2
⇒x+
A
z1 + z 2 ≤ z 1 + z 2 ;
32. If x=Cosθ+iSinθ then
K
x+a x −a −i where x = 2 2
nπ 15. (1 + 3i) n + (1 − 3i)n = 2n +1 Cos 3
z1 + z 2 ≥ z 1 − z 2 ;
z1 − z 2 ≥ z 1 − z 2
S
If three complex numbers Z1, Z2, Z3 are collinear then z1 z1 1 z z 2 2 1 = 0 z 3 z 3 1
1 ⇒ x n − n = 2Sinn α x
⇒ xn +
1 = 2Cosnα xn
33. If ΣCosα = ΣSinα = 0 ΣCos2α = ΣSin2α = 0 ΣCos2nα = ΣSin2nα = 0, ΣCos2α = ΣSin2α = 3/2 ΣCos3α = 3Cos(α + β + γ), ΣSin3α = 3Sin(α + β + γ) ΣCos(2α – β – γ) = 3, ΣSin(2α – β – γ) = 0, 34. a3 + b3 + c3 – 3abc = (a + b + c) (a + bω + cω2) (a + bω2 + cω)
b a
Sum of roots = − , product of roots c , discriminate = b2 – 4ac a
20. If Z1 − Z1Z2 + Z2 = 0 then origin, Z1, Z2 forms an equilateral triangle 21. If Z1, Z2, Z3 forms an equilateral triangle and Z0 is circum center then 2
Z12 + Z 2 2 + Z32 = 3Z02 ,
22. If Z1, Z2, Z3 forms an equilateral triangle and Z0 is circum center then Z12 + Z2 2 + Z32 = Z1 Z2 + Z2 Z3 + Z3 Z1
1 1 = 2Cosα ⇒ x − = 2Sin α x x
1. Standard form of Quadratic equation is ax2 + bx +c = 0
3 2 Z 4 2
1 =Cosθ–iSinθ x
Quadratic Expressions
18. Area of triangle formed by Z, IZ, Z + Zi 1 is Z2 2 19. Area of triangle formed by Z, ωZ, Z + ωZ is
π i 2
Cisβ = Cis( α + β) Cisβ
= −i,(1 + i) 2 = 2i,(1 − i) 2 = −2i
17.
i
30. (Cosθ + iSinθ)n = Cosnθ + iSinnθ 31. Cosθ+iSinθ=CiSθ, Cisα. Cisβ=Cis (α+ β),
1+ i 1− i = i, 1− i 1+ i
+1
H π
e 2 = i,log i =
12. Arg = Arg z1 − Argz2 13. Arg z = − Argz
n
z1 − z2 AB iθ = e z1 − z3 AC
29. eiθ = Cosθ + iSinθ = Cosθ, eiπ = –1,
z1 z2
16. (1 + i) n + (1 − i)n = 2 2 Cos
AB, AC then
I
it is less, then it represents hyperbola 28. A(z1),B(z2),C(z3), and θ is angle between
11. Arg z1z2 = Arg z1 + Argz2
=
kz 2 ± z1 k ±1
27. z − z1 + z − z2 = k, k > z1 − z2 then locus
y 10. Arg of –x – iy is θ = −π + tan −1 for every x x > 0, y > 0
a + ib =
ant
If k = 1 the locus of z represents a line or perpendicular bisector.
x>0,y>0
14. i = −1,
α 2 − β where α is nonreal complex and β is const
With radius
ends of diameter
y for every x
for every
25. zz + zα + zα + β = 0 Represents circle
z − z2
x > 0, y > 0
y 9. Arg of –x + iy is θ = π − tan −1 x
24. z − z 0 = is a circle with radius p and center z0
26. If z − z1 = k (k≠1) represents circle with
b 6. Arg z = tan −1 principle value of θ is a –π∠θ≤π y 7. Arg of x + iy is θ = tan −1 for every x
8. Arg of x – iy is θ = − tan −1
23. Distance between two vertices Z1, Z2 is .z1 − z2
If α, β are roots then Quadratic equation is x2 – x(α + β) + αβ = 0 2. If the roots of ax2 + bx + c = 0 are 1, c a then a + b + c = 0 3. If the roots of ax2 + bx + c = 0 are in ratio m : n then mnb2 = (m + n)2 ac 4. If one root of ax2 + bx + c = 0 is square of the other then ac2 + a2c + b3 = 3abc 5. If x > 0 then the least value of x +
1 is 2 x
6. If a1, a2,....., an are positive then the least value of
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