(cos(2x)-cos(4x))/(cos(2x)+cos(4x)) how does this fraction turn into (-2sin(3x)sin(-x))/(2cos(3x)cos( can you do a step by step proof to show how the 1st expression turns into the second expression?

Recall the the angle sum identity for cosine.




Adding the two equations together gives



while subtracting gives



Replacing and , you get



Finally, , so you get the second expression.

The answer is a because i went through all the other ones that it didn’t come out right

Answer:

$4034.40

step-by-step explanation:

the perimeter of the field is the sum of the lengths of the four sides:

47 yd + 158 yd + 47 yd + 158 yd = 410 yd

the cost of 3 ft (1 yd) of fence is 3×$3.28 = $9.84.

so the cost of jake's wood perimeter fance is

(410 yd) × ($9.84 /yd) = $4034.40