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Let (1 + x)^(36) = a(0) +a(1) x + a(2) x...

Let `(1 + x)^(36) = a_(0) +a_(1) x + a_(2) x^(2) +...+ a_(36)x^(36)`. Then
Statememt-1: `a_(0) +a_(3) +a_(6) +…+a_(36)= (2)/(3) (2^(35) +1)`
Statement-2: `a_(0) + a_(2) +a_(4) +…+ a_(36) = 2^(35)`

A

1

B

2

C

3

D

4

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the two statements given regarding the coefficients of the expansion of \((1 + x)^{36}\). ### Step 1: Understanding the Coefficients The coefficients \(a_k\) in the expansion of \((1 + x)^{36}\) can be expressed using the binomial theorem: \[ (1 + x)^{36} = \sum_{k=0}^{36} a_k x^k = \sum_{k=0}^{36} \binom{36}{k} x^k \] Thus, \(a_k = \binom{36}{k}\). ### Step 2: Analyzing Statement 1 Statement 1 claims: \[ a_0 + a_3 + a_6 + \ldots + a_{36} = \frac{2}{3} (2^{35} + 1) \] To find this sum, we can use the roots of unity filter. We will use the cube roots of unity, denoted as \(1, \omega, \omega^2\), where \(\omega = e^{2\pi i / 3}\). 1. **Calculate \(S_0\)**: \[ S_0 = (1 + 1)^{36} = 2^{36} \] 2. **Calculate \(S_1\)**: \[ S_1 = (1 + \omega)^{36} = (1 - \omega^2)^{36} = (-\omega^2)^{36} = \omega^{72} = 1 \] 3. **Calculate \(S_2\)**: \[ S_2 = (1 + \omega^2)^{36} = (1 - \omega)^{36} = (-\omega)^{36} = \omega^{36} = 1 \] Now, we can sum these results: \[ S_0 + S_1 + S_2 = 2^{36} + 1 + 1 = 2^{36} + 2 \] ### Step 3: Using Roots of Unity The sum of coefficients at indices that are multiples of 3 can be found using: \[ \frac{S_0 + S_1 + S_2}{3} = \frac{2^{36} + 2}{3} \] This simplifies to: \[ \frac{2^{36} + 2}{3} = \frac{2(2^{35} + 1)}{3} \] Thus, we have: \[ a_0 + a_3 + a_6 + \ldots + a_{36} = \frac{2}{3}(2^{35} + 1) \] This confirms that Statement 1 is true. ### Step 4: Analyzing Statement 2 Statement 2 claims: \[ a_0 + a_2 + a_4 + \ldots + a_{36} = 2^{35} \] To find this sum, we can use the same approach with \(x = 1\) and \(x = -1\): 1. **Calculate \(S_0\)** (as before): \[ S_0 = 2^{36} \] 2. **Calculate \(S_{-1}\)**: \[ S_{-1} = (1 - 1)^{36} = 0 \] Adding these two results: \[ S_0 + S_{-1} = 2^{36} + 0 = 2^{36} \] Now, we can express the sums of even and odd indexed coefficients: \[ S_0 = a_0 + a_2 + a_4 + \ldots + a_{36} + (a_1 + a_3 + a_5 + \ldots + a_{35}) \] \[ S_{-1} = a_0 - a_1 + a_2 - a_3 + \ldots + a_{36} = 0 \] Adding these two equations gives: \[ 2(a_0 + a_2 + a_4 + \ldots + a_{36}) = 2^{36} \] Thus, \[ a_0 + a_2 + a_4 + \ldots + a_{36} = 2^{35} \] This confirms that Statement 2 is also true. ### Conclusion Both statements are true, but Statement 2 is not the correct explanation for Statement 1. Thus, the final answer is that both statements are true, but Statement 2 does not explain Statement 1.

To solve the problem, we need to analyze the two statements given regarding the coefficients of the expansion of \((1 + x)^{36}\). ### Step 1: Understanding the Coefficients The coefficients \(a_k\) in the expansion of \((1 + x)^{36}\) can be expressed using the binomial theorem: \[ (1 + x)^{36} = \sum_{k=0}^{36} a_k x^k = \sum_{k=0}^{36} \binom{36}{k} x^k \] Thus, \(a_k = \binom{36}{k}\). ...
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