Question 9 of 20
1 answer:
You might be interested in
9514 1404 393
Answer:
lower left
Step-by-step explanation:
We notice that the answer choices have only the first equation changed. The equivalent of the first equation must have the same ratios of coefficients.
x-coefficient : y-coefficient : constant
= 2 : 1 : -15 . . . . . in the given equation
2 : -2 : 30 = 1 : -1 : 15 . . . upper left — not the same
-4 : -2 : -15 = 4 : 2 : 15 . . . upper right — not the same
-4 : -2 : 30 = 2 : 1 : -15 . . . lower left — same as the given equation
-4 : 1 : 30 = 4 : -1 : -30 . . . lower right — not the same
Answer:
cos(x-30)=1/2
Step-by-step explanation:
We use the following relationship to obtain cos(x)
From that, we have that cos(x)= sqrt(1-1/4)=sqrt(3) / 4
To obtain the value of cos(x-30), lets remember the following expression:
Therefor, we can use that to obtain our desired function cos(x-30)
cos(x)*cos(30)+sin(x)*sin(30)
=2/4=1/2