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:
1)-9x^5 + 7x^2 + 3 2) -2x2 • (x - 7) 3) -23v^2 + 7v + 4 4) is just 7x
Answer with Step-by-step explanation:
We are given that

For each real number 
To prove that f is one -to-one.
Proof:Let
and
be any nonzero real numbers such that

By using the definition of f to rewrite the left hand side of this equation

Then, by using the definition of f to rewrite the right hand side of this equation of 

Equating the expression then we get




Therefore, f is one-to-one.
Answrer
Find out the what is the perimeter of the rectangle .
To prove
Now as shown in the figure.
Name the coordinates as.
A(−3, 4) ,B (7, 2) , C(6, −3) , and D(−4, −1) .
In rectangle opposite sides are equal.
Thus
AB = DC
AD = BC
Formula

Now the points A(−3, 4) and B(7, 2)





Thus

Now the points
A (−3, 4) , D (−4, −1)




Thus
Formula
Perimeter of rectangle = 2 (Length + Breadth)
Here






Perimeter of a rectangle = 30.6 units.
Therefore the perimeter of a rectangle is 30.6 units.
28% of 1500 is 420.
so add it to 1500 and you’ll get 1920