Answer:
8
Step-by-step explanation:
Nth term of a geometric sequence is given as:
...(1)
Plugging n = 9, a = 3 and r = 2 in the above equation, we find:
... (2)
Comparing equations (1) & (2), we obtan:
(n - 1) = 8
Answer:
A), B) and D) are true
Step-by-step explanation:
A) We can prove it as follows:
B) When you compute the product Ax, the i-th component is the matrix of the i-th column of A with x, denote this by Ai x. Then, we have that . Now, the colums of A are orthonormal so we have that (Ai x)^2=x_i^2. Then .
C) Consider . This set is orthogonal because , but S is not orthonormal because the norm of (0,2) is 2≠1.
D) Let A be an orthogonal matrix in . Then the columns of A form an orthonormal set. We have that . To see this, note than the component of the product is the dot product of the i-th row of and the jth row of . But the i-th row of is equal to the i-th column of . If i≠j, this product is equal to 0 (orthogonality) and if i=j this product is equal to 1 (the columns are unit vectors), then
E) Consider S={e_1,0}. S is orthogonal but is not linearly independent, because 0∈S.
In fact, every orthogonal set in R^n without zero vectors is linearly independent. Take a orthogonal set and suppose that there are coefficients a_i such that . For any i, take the dot product with u_i in both sides of the equation. All product are zero except u_i·u_i=||u_i||. Then then .
Answer:
Y = 27
Step-by-step explanation:
Y * 3 = 81
Divide each side by 3
Y * 3/3 = 81/3
Y = 27
Given
49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively.
To find:
Which of these types of sampling is used: random, stratified, systematic, cluster, convenience?
Explanation:
It is given that,
49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively.
That implies,
Since Stratified random sampling is a method of sampling that involves dividing a population into smaller groups–called strata.
Then, the random sampling used is Stratified Random Sampling.