The product of trigonometric functions can be converted into sum ans vice versa. The given function is a product and we can convert it to a sum.One way is to expand the given expression and simplify it to find the result.
The second and easier option is to just remember the formulas of product to sum conversion identities. The 4 formulas for this case are listed below in the image.
Since we have the product of cos and sin, the sum will involve two sine functions connected by addition. 
So the correct answer is option A
 
        
        
        
Answer:
88 inches
Step-by-step explanation:
The given bicycle has a tyre that is 28 inches in diameter.
How far the bicycle moves forward each time the wheel goes around is the circumference of the bicycle tyre.
This is calculated using the formula:
C =\pi \: d
We substitute the diameter and
\pi =  \frac{22}{7} 
C =  \frac{22}{7}  \times 28
This simplifies to
C =22 \times 4
88 \: inches
 
        
             
        
        
        
There are several information's already given in the question. Based on those information's, the answer can be easily deduced.
The equation given in the question is
x = 0.8x + 72
x - 0.8x = 72
0.2x = 72
x = 360
Now 
Number of people that became 
member of the site = (80/100) * 360
                               = 288 people
From the above deduction, it can concluded that the correct option among all the options that are given in the question is 288.
        
                    
             
        
        
        
Answer:
m<4=40
Step-by-step explanation:
Supplementary angles form 180 degrees
m<3 is vertical to the 50 degree angle which is equal. 
so. m<3=50
m<5=90
90+50=140
180-140=40
m<4=40
 
        
             
        
        
        
<u>Answer:</u>
24
<u>Step-by-step explanation:</u>
Y is 60% of 40
Equation: Y = P% * X
<u>Solving our equation for Y</u>
Y = P% * X
Y = 60% * 40
<u>Converting percent to decimal:</u>
p = 60%/100 = 0.6
Y = 0.6 * 40
Y = 24