Hi there!

We are given:
cos(7x)cos(4x) = -1 - sin(7x)sin(4x)
Begin by moving all terms with variables to one side:
cos(7x)cos(4x) + sin(7x)sin(4x) = -1
The corresponding trig identity is cos(A - B). Thus:
cos(7x - 4x) = cos(7x)cos(4x) + sin(7x)sin(4x) = -1
cos(3x) = -1
cos = -1 at π, so:
3x = π
x = π/3
We can also find another solution. Let 3π = -1:
3x = 3π
x = π
Thus, solutions on [0, 2π) are π/3 and π.
Answer:
add all of them together (x and y’s) the divide the sum by the amt of numbers
Step-by-step explanation:
Answer:
Single Blind (option 1)
Step-by-step explanation:
The subjects don't know which cream they have but the technicians do.
If the subject knows which cream they have then they can be influenced by the placebo effect. If they don't know but the technicians do then the technicians will be able to look at unbiased responses from the subjects and tell if it works or not. If the technicians don't know which cream each subject has then they won't be able to learn anything from the responses. The technicians need to know which cream each subject has and the subjects can't know which cream they had.
Answer:
It is probably 21x-3y= -2
Answer:
8.
Step-by-step explanation:
The slope =
difference in y coordinates of 2 points / difference in coordinates of corresponding x coordinates.
So taking the first 2 points:
The slope = (18-10) / 0 - (-1)
= 8/1
= 8.
This is confirmed by slope between the second and third points
slope = 26-18/ (1-0) = 8.