Recall the angle sum identities:
cos(a + b) = cos(a) cos(b) - sin(a) sin(b)
cos(a - b) = cos(a) cos(b) + sin(a) sin(b)
sin(a + b) = sin(a) cos(b) + sin(b) cos(a)
sin(a - b) = sin(a) cos(b) - sin(b) cos(a)
Notice that adding the first two together, and subtract the last from the third, we get two more identities:
cos(a + b) + cos(a - b) = 2 cos(a) cos(b)
sin(a + b) + sin(a - b) = 2 sin(b) cos(a)
Let a = 4x and b = x. Then
cos(5x) + cos(3x) = 2 cos(4x) cos(x)
sin(5x) - sin(3x) = 2 sin(x) cos(4x)
Now,

as required.
Answer:
Step-by-step explanation:
3 6 9 12 15
5 .
10 .
15 .
20 .
25 .
Answer:
9t^2+(t+2)^2
Step-by-Step:
t is 9 X t, or the product of 9 and t. ^2 is squared while + is increased t+2 is the sum of t and t. the ^2 after the parenthesis is indicating the "square of t and 2"
We need to find the value of the hypotenuse in order to solve this problem.
12^2+4^2=H^2
Therefore:
H=√(144+16)
H=4√10
Now:
sin(G)=O/H=4/(4√10)
=1/(√10)
=(√10)/10