Answer: x=2π/3 and x=4π/3
Step-by-step explanation:
The equation we have is 
. All we have to do is get cosine alone to find the 2 values of x.
Now that we have our cosine left, we can use our unit circle to figure out when does cosx=-1/2. Cosine is the x value of the coordinate.
x=2π/3
x=4π/3
Answer:
there may be 16 but I am not sure
21 because 9+10 is actually 21
Answer:
7 digits can be used for each position
There are a total of 5 positions
N = 7^5 = 16,807 numbers
You have 7 choices for the first position, second position, etc.
So there is an identity we'll need to use to solve this:
cos(x+y) = cosxcosy - sinxsiny
replace the numerator with the right hand side of that identity and we get:
(cosxcosy - sinxsiny)/cosxsiny
Separate the numerator into 2 fractions and we get:
cosxcosycosxsiny- sinxsiny/cosxsiny
the cosx's cancel on the left fraction, the siny's cancel on the right fraction and we're left with:
cosy/siny - sinx/cosx
which simplifies to:
coty - tanx
