Answer: 
Step-by-step explanation:
According to the trigonometric identities we have the following formula:

Now, we have the following:

Where
and 
Hence:


Finally:

Answer:
m=3
Step-by-step explanation:
m= 8-(5)/2-(1)
Answer:
the area is 25/4 π
Step-by-step explanation:
diameter is 5 m
area will be 25/4π
Answer:
She returned 5 gifts.
Step-by-step explanation:
36 gifts is 60% = 0.6 of all the gifts that she received. How many presents are 100% = 1?
36 gifts - 0.6
x gifts - 1
0.6x = 36
x = 36/0.6
x = 60
She received 60 gifts.
She opened the rest of the gifts and found that 25% of them were the same present
The rest is 60 - 36 = 24 gifts.
25% is (1/4)*24 = 6 duplicate figts
She returned all but one of the duplicate gifts.
That is, she returned 6 - 1 = 5 gifts.