A matrix is diagonal if

In other words, you want non-zero elements only when the indices of the row and the column are the same: the first element of the first row must be non zero, the second element of the second row must be non-zero, and so on. All other elements must be zero.
<span>A. cos(x) = cos(-x) [correct, since cos(x) is an even function]
B. Since the cosine function is even, reflection over the x-axis [y-axis] does not change the graph. [false]
C. cos(x) = -cos(x) [ false]
D. The cosine function is odd [even], so it is symmetrical across the origin. [false]</span>
Answer:
sometimes
Step-by-step explanation:
There are several ways that dilation is used in real life. Here are several:
In graphic design. I actually do some graphic design, and I use dilation a lot. It is common to dilate photos to fit the space that you want it to fit.
In police work and crime investigation. Detectives and police dilate photos to see smaller details and evidence.
In architecture. It is normal for architects to make a prototype of their design or building. In order to make the building true to the prototype, they must dilate the scale and measurements.
In the doctor's office. Dilation is used in eye exams so that the eye doctor can view the patient's eye better. After a while it will slowly reduce in size and return back to normal.
We can use the sum of an aritmetic sequence
the sum from n=1 to n=r when the first term is a1 and the nth term is an is

first term is 1
last term is 100
there are 100 terms so n=100
so the sum is


S=5050
now you want us to divide by 10
5050/10=505
fun fact, gauss (famous math guy) did this when he was younger, legend has it that he was assigned this as an in class assigment to kill time but gauss found a neat pattern, he noticed that adding the end terms wer giving the same sum, example, 100+1=101, 2+99=101, etc, so he just needed to find al the pairs and add them all up
answer is 505
the result is 505