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
.
In the given equation, as the value of <em>y</em> increase, the value of <em>x</em> also
increases.
- Yes, 4·y = 16·x is a direct variation
Reasons:
A direct variation is a relationship that exists between two variables. It is
also known as a direct proportion which can be expressed as; y = k·x
Where <em>k</em> is a number
The given equation is 4·y = 16·x
Dividing both sides by 4 gives;

Which gives;
y = 4·x
Comparing the above equation with the equation for a direct variation gives;
y = 4·x
y = k·x
Therefore;
k = 4
The equation, y = 4·x, and therefore, the equation from which it is derived, 4·y = 16·x, is a direct variation.
Learn more about direct variation here:
brainly.com/question/6499629
The word "associative" comes from "associate" or "group";the Associative Property is the rule that refers to grouping. For addition, the rule is "<span>a + (b + c) = (a + b) + c</span><span>"; in numbers, this means
</span>2 + (3 + 4) = (2 + 3) + 4. For multiplication, the rule is "<span>a(bc) = (ab)c</span>"; in numbers, this means2(3×4) = (2×3)4<span>. Any time they refer to the Associative Property, they want you to regroup things; any time a computation depends on things being regrouped, they want you to say that the computation uses the Associative Property.</span>
Area of square = 10x10
= 100
area of circle = pi(r)^2
= pi (5)^2
=25pi
area of shaded = 100 -25pi
circumference of circle = 2pi (r)
= 2pi(5)
= 10pi
perimeters of shaded = 10pi + 10 + 10
= 10pi +20
Answer:
Since the focus is at (-6,-11) and the directrix is at y=9:
The vertex is halfway between the focus and the directrix, so the vertex is at (-6,-1). (Draw this on graph paper if that doesn't make sense.)
The general form (conics form) of a parabola: 4p(y-k)=(x-h)^2 (vertex is (h,k) and "p" is the distance between the focus and vertex (or between vertex and directrix)).
(h,k) = (-6,-1)
p = 10 (distance between focus and vertex), so 4p = 40.
Therefore:
40(y+1)=(x+6)^2
Or if you need to rearrange to "vertex form": y=(1/40)(x+6)^2 - 1
Step-by-step explanation: