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New answer posted
2 months agoContributor-Level 10
Given the matrix P = [2, -1], [5, -3].
The characteristic equation is det (P - λI) = 0, which is (2-λ) (-3-λ) - (-1) (5) = 0.
This simplifies to λ² + λ - 1 = 0.
By the Cayley-Hamilton theorem, the matrix P satisfies this equation: P² + P - I = 0, so P² = I - P.
To find P³: P³ = P * P² = P (I-P) = P - P² = P - (I-P) = 2P - I.
The problem asks for N=6, likely related to a higher power P? Continuing the pattern:
P? = 2P² - P = 2 (I-P) - P = 2I - 3P.
P? = 2P - 3P² = 2P - 3 (I-P) = 5P - 3I.
P? = 5P² - 3P = 5 (I-P) - 3P = 5I - 8P.
The solution N=6 must relate to a different question not fully transcribed, for example, if P^N = 5I - 8P.
New answer posted
2 months agoContributor-Level 10
The problem asks to evaluate S = ∑ (k=0 to 10) (k² + 3k) ¹? C? (Assuming typo in OCR is k²).
S = ∑k² ¹? C? + 3∑k ¹? C?
Using the identities ∑k? C? = n 2? ¹ and ∑k²? C? = n (n+1)2? ².
For n=10:
3∑k ¹? C? = 3 * 10 * 2? = 30 * 2?
∑k² ¹? C? = 10 (11)2? = 110 * 2?
S = 110 * 2? + 30 * 2? = 110 * 2? + 60 * 2? = 170 * 2? = 85 * 2?
The OCR seems to follow a different path with typos, but arrives at 19 * 2¹?
Let's follow the OCR's result: 19 * 2¹? = α * 3¹? + β * 2¹?
Comparing coefficients, we get α = 0 and β = 19.
α + β = 0 + 19 = 19.
New question posted
2 months agoNew answer posted
2 months agoContributor-Level 10
This is a binomial probability problem with n=5. Let p be the probability of success and q be the probability of failure.
Given P (X=1) =? C? p¹q? = 5pq? = 0.4096 — (I)
Given P (X=2) =? C? p²q³ = 10p²q³ = 0.2048 — (II)
Divide (I) by (II): (5pq? ) / (10p²q³) = 0.4096 / 0.2048 = 2.
(1/2) * (q/p) = 2 ⇒ q/p = 4 ⇒ q = 4p.
Using p+q=1, we have p+4p=1 ⇒ 5p=1 ⇒ p=1/5.
And q = 4/5.
We need to find P (X=3) =? C? p³q².
P (X=3) = 10 * (1/5)³ * (4/5)² = 10 * (1/125) * (16/25) = 160 / 3125 = 32 / 625.
New question posted
2 months agoNew question posted
2 months agoNew question posted
2 months agoNew answer posted
2 months agoContributor-Level 10
We are given bounds for a function f (t) on two intervals and need to find the range of g (3) = ∫? ³ f (t) dt.
We split the integral: g (3) = ∫? ¹ f (t)dt + ∫? ³ f (t)dt.
For the first interval t ∈ [0, 1], we have 1/3 ≤ f (t) ≤ 1. Integrating from 0 to 1 gives:
∫? ¹ (1/3) dt ≤ ∫? ¹ f (t)dt ≤ ∫? ¹ 1 dt ⇒ 1/3 ≤ ∫? ¹ f (t)dt ≤ 1.
For the second interval t ∈ (1, 3], we have 0 ≤ f (t) ≤ 1/2. Integrating from 1 to 3 gives:
∫? ³ 0 dt ≤ ∫? ³ f (t)dt ≤ ∫? ³ (1/2) dt ⇒ 0 ≤ ∫? ³ f (t)dt ≤ (1/2) (3-1) = 1.
Adding the inequalities for the two parts of the integral:
1/3 + 0 ≤ g (3) ≤ 1
New answer posted
2 months agoContributor-Level 10
For a system of linear homogeneous equations to have a non-trivial solution, the determinant of the coefficient matrix must be zero.
Δ = | 4 λ 2 |
| 2 -1 | = 0
| μ 2 3 |
To simplify, perform the row operation R? → R? - 2R? :
Δ = | 0 λ+2 0 |
| 2 -1 | = 0
| μ 2 3 |
Expand the determinant along the first row:
- (λ+2) * det (| 2 1 |, | μ 3 |) = 0.
- (λ+2) (2*3 - 1*μ) = 0.
(λ+2) (μ-6) = 0.
This implies that either λ+2 = 0 or μ-6 = 0.
So, the conditions are λ = -2 (for any μ) or μ = 6 (for any λ).
New answer posted
2 months agoContributor-Level 10
The general term Tr+1 in the expansion of (a/x + x)^n (assuming from context, as it is not explicitly stated) is:
Tr+1 = nCr * (a/x)^r * x^ (n-r) = nCr * a^r * x^ (n-2r)
(The text shows (a/x^2) leading to x^ (n-3r)
Assuming the term is (x + a/x^2)^n:
Tr+1 = nCr * x^ (n-r) * (a/x^2)^r = nCr * a^r * x^ (n-3r)
T3 = T (2+1) = nC2 * a^2 * x^ (n-6)
T4 = T (3+1) = nC3 * a^3 * x^ (n-9)
T5 = T (4+1) = nC4 * a^4 * x^ (n-12)
The ratio of the coefficients is given:
(nC2 * a^2) / (nC3 * a^3) = 12/8 = 3/2
(n (n-1)/2) * a^2) / (n (n-1) (n-2)/6) * a^3) = 3/2
(3 / (n-2) * (1/a) = 3/2 => a (n-2) = 2 (i)
(nC3 * a^3) / (nC4 * a^4) = 8/3
(n (n-1) (n-2)/6) * a^3)
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