Core Pure 1 Flashcards
(70 cards)
2.3 What does mod(z1z2) equal?
mod(z1z2) = mod(z1) mod(z2)
2.3 What does arg(z1z2) equal?
arg(z1z2) = arg(z1) + arg(z2)
2.3 What does mod(z1/z2) equal?
mod(z1/z2) = mod(z1)/mod(z2)
2.3 What does arg(z1/z2) equal?
arg(z1/z2) = arg(z1) - arg (z2)
3.1 What is the formula of the sum of the first n integers?
Σ(r=1 -> n) r = ((1/2)n)(n+1)
3.2 What is the formula for the sum of the first n squares?
Σ (r=1 -> n) r^2 = ((1/6)n)(n+1)(2n+1)
3.2 What is the formula for the sum of the first n cubes?
((1/4)n^2)(n+1)^2
3.1 Σ(r=1 -> n) (ar + b) = ?
aΣ(r=1 -> n)r + bΣ(r=1 -> n)1
4.1 What do the sum of 2 roots of a quadratic equal?
α + β = -b/a
4.1 What do the product of 2 roots of a quadratic equal?
αβ = c/a
4.2 What do the sum of 3 roots of a cubic equal?
α + β + γ = -b/a
4.2 What do the sum of all 3 of the pairs of products of a cubic equal?
αβ + αγ + βγ = c/a
4.2 What do the product of all 3 roots of a cubic equal?
αβγ = -d/a
4.3 What do the sum of 4 roots of a quartic equal?
α + β + γ + δ = -b/a
4.3 What do the sum of all 6 pairs of a quartic equal?
αβ + αγ + αδ + βγ + βδ + γδ = c/a
4.3 What do the sum of all 4 triples of a quartic equal?
αβγ + αβδ + αγδ + βγδ = -d/a
4.3 What does the product of all 4 roots of a quartic equal?
αβγδ = e/a
4.4 Give the rules for the sums of the reciprocals of the roots of a polynomial (quadratic, cubic, quartic)
Quadratic: (1/α) + (1/β) = (α + β)/αβ
Cubic: (1/α) + (1/β) + (1/γ) = (Σαβ)/αβγ
Quartic: (1/α) + (1/β) + (1/γ) + (1/δ) = (Σαβγ)/αβγδ
4.4 Give the rules for the products of powers of the roots of a polynomial (quadratic, cubic, quartic)
Quadratic: (α^n)(β^n) = (αβ)^n
Cubic: (α^n)(β^n)(γ^n) = (αβγ)^n
Quartic: (α^n)(β^n)(γ^n)(δ^n) = (αβγδ)^n
4.4 Give the rules of the sums of squares of the roots of a polynomial (quadratic, cubic, quartic)
Quadratic: α^2 + β^2 = (α + β)^2 - 2αβ
Cubic: α^2 + β^2 + γ^2 = (α + β + γ)^2 - 2(αβ + αγ + βγ)
Quartic: α^2 + β^2 + γ^2 + δ^2 = (α + β + γ + δ)^2 -2(αβ + αγ + αδ + βγ + βδ + γδ)
4.4 Give the rules of the sums of cubes of the roots of a polynomial (quadratic, cubic)
Quadratic: α^3 + β^3 = (α + β)^3 - 3αβ(α + β)
Cubic: α^3 + β^3 + γ^3 = (α + β + γ)^3 - 3(α + β + γ)(αβ + αγ + βγ) + 3αβγ
4.5 e.g. The cubic x^3 - 2x^2 + 3x - 4 = 0 has roots α, β, & γ, find the equation with roots 2α, 2β, and 2γ
Let w = 2x
x = w/2
Substitute x = w/2 into the cubic, simplify until coefficients are integers
5.1 What is the formula for the volume of a revolution around the x-axis?
Volume = π∫(a->b)(y^2)dx
5.2 What is the formula for the volume of a revolution around the y-axis?
Volume = π∫(a->b)(x^2)dy