Answer:
2.63274768567
Step-by-step explanation:
First, note that 3.1415... is p, so 2(3.1415...) is 2pi and 4(3.1415...) is 4pi. 
2pi and 4pi are full rotations, which will lead to the same cosine (i.e. cos(x) = cos (x+2pi) = cos(x+4pi) = ... = cos (x+2k*pi)). 
So, the expression equals cos0.5 + cos 0.5 + cos0.5 = 3cos0.5 = 3(0.87758256189) = 2.63274768567
I hope this helps! :)
 
        
             
        
        
        
36 x 8 = 288
44 x 8 = 352
288 + 352 = 640
So 640 minutes in 8 days.
        
                    
             
        
        
        
These are the two rules for when a and b are positive numbers.
a + b = b + a
a - b ≠ b -a
a - b = -b + a
For example:
5.71 + 2.84 = 2.84 + 5.71
8.55 = 8.55
5.71 - 2.84 ≠ 2.84 - 5.71
2.87 ≠ -2.87
5.71 - 2.84 = -2.84 + 5.71
2.87 = 2.87
These are the rules for when a and b are negative numbers.
a + b = b + a
a - b = b + a
For example,
-6.2 + (-3.96) = -3.96 + (-6.2)
-6.2 - 3.96 = -3.96 - 6.2
-10.16 = -10.16
-6.2 - (3.96) = -3.96 + (-6.2)
-10.16 = -10.16
Also, if a is a positive number, while b is a negative number, we see these rules:
a + b = a - b
a - b = a + b
For example,
5.71 + (-6.2) = 5.71 - 6.2
-0.49 = -0.49
5.71 - (-6.2) = 5.71 + 6.2
11.91 = 11.91
Also, if a is a negative number while b is a positive number, then these rules will apply:
a + b = b - a
a - b = -b - a
For example,
-3.96 + 2.84 = 2.84 - 3.96
-1.12 = <span>-1.12
</span>
-3.96 - 2.84 = -2.84 - 3.96
-6.8 = -6.8
I hope this helps! :)
        
             
        
        
        
Step-by-step explanation:
Case 1 :


Case 2 :

