Answer:
Identity (a) can be re-written as

which we already proven in another question, while for idenity (b)

step A is simply expressing each function in terms of sine and cosine.
step B is adding the terms on the LHS while multiplying the one on RHS.
step C is replacing the term on the numerator with the equivalent from the pithagorean identity 
Answer:
Just search from other websites
Step-by-step explanation:
easy
2x^2+4x+2
Carry the 2 over to the 3 behind the 4 and multiply so 2times2 is 4. So i new equation is.
X^2+4x+4
Now you have to find the factors of 4 which is 1,4 and 2,2
So now you have to see which one adds up to 4 so 1+4 is 5 so cross that out and 2+2=4.
So the two number is 2 and 2 now you have to bring down the x^2 and the signs.
(X+2) (X+2) and thats your answer
<span>3[(15 - 3) squared divided by 4]
=</span><span>3[(15 - 3)^2 / 4]
=3</span>[(12)^2 / 4]
=3[144 / 4]
=3[36]
=108