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
Answer:

Step-by-step explanation:
Given
The above table
Required
Determine the probability of a sum that is a multiple of 6
Represent the event that an outcome is a multiple of 6 with M.
List out all possible values of M

Number of M is

Total possible outcome is:

The theoretical probability is then calculated as follows:

In this case, it is:


Simplify fraction

Answer:
In the expression of 7xy, if x is negative, then y must also be negative for the product to be positive.
Let me know if this helps!