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
Answer: 4^-2 and 2^-4.
Step-by-step explanation: You chose the right ones.
Answer:
a11 = -53
Step-by-step explanation:
an = -6n +13
We want the 11th term, so n =11
a11 = -6(11) +13
= -66 +13
= -53
Answer:
D
Step-by-step explanation:
Sam should have bought 3.09 yards of fabric instead of 2.4 yards
So, Option D is correct.
Step-by-step explanation:
Total fabric needed by Sam = 2.75
According to directions on a sewing pattern they say to buy an extra 12.5%
So, extra fabric would be: 12.5% of 2.75
Solving
Now adding 0.343 into 2.75 to get extra fabric quantity:
2.75+0.343
=3.09
Therefore Sam should have bought 3.09 yards of fabric instead of 2.4 yards
So, Option D is correct.