What we need to proof is this: "Assuming X a vector space over a scalar field C. Let X= {x1,x2,....,xn} a set of vectors in X, where $n\geq 2$ . If the set X is linearly dependent if and only if at least one of the vectors in X can be written as a linear combination of the other vectors"

Proof

Since we have a if and only if w need to proof the statement on the two possible ways.

If X is linearly dependent, then a vector is a linear combination

We suppose the set $X= (x_1, x_2,....,x_n)$ is linearly dependent, so then by definition we have scalars $c_1,c_2,....,c_n$ in C such that:

$c_1 x_1 +c_2 x_2 +.....+c_n x_n =0$

And not all the scalars $c_1,c_2,....,c_n$ are equal to 0.

Since at least one constant is non zero we can assume for example that $c_1 \neq 0$ , and we have this:

$c_1 v_1 = -c_2 v_2 -c_3 v_3 -.... -c_n v_n$

We can divide by c1 since we assume that $c_1 \neq 0$ and we have this:

$v_1= -\frac{c_2}{c_1} v_2 -\frac{c_3}{c_1} v_3 - .....- \frac{c_n}{c_1} v_n$

And as we can see the vector $v_1$ can be written a a linear combination of the remaining vectors $v_2,v_3,...,v_n$ . We select v1 but we can select any vector and we get the same result.

If a vector is a linear combination, then X is linearly dependent

We assume on this case that X is a linear combination of the remaining vectors, as on the last part we can assume that we select $v_1$ and we have this:

$v_1 = c_2 v_2 + c_3 v_3 +...+c_n v_n$

For scalars defined $c_2,c_3,...,c_n$ in C. So then we have this:

$v_1 -c_2 v_2 -c_3 v_3 - ....-c_n v_n =0$

So then we can conclude that the set X is linearly dependent.

And that complet the proof for this case.

5 0

3 years ago

cassidy loves black and yellow jelly beans she noticed when she was counting them that she had 7 less than three times as many b

Dmitriy789 [7]

Most of the information's are already given in the question. It is important to understand the language of the problem for solving the problem. Once the language is understood, then solving the problem is easy.
Let us assume the number of black jelly beans = x
Number of yellow jelly beans = y
Then from the question we can get to a equation.
3x - 7 = y
We also know from the question that
x + y = 225
x + 3x -7 = 225
4x = 225 + 7
4x = 232
x = 232/4
= 58
So Cassidy has 58 black jelly beans out of the total of 225 jelly beans

4 0

3 years ago

Solve for X.Enter the solutions from least to greatest.

FinnZ [79.3K]

Answer:

lesser x= -10.32

greater x= -3.68

Step-by-step explanation:

$- 7 + \sqrt{11} = - 3.68$