Answer:
hence cos ( 2 A ) = cos 2 A − ( 1 − cos 2 A ) = 2 cos 2 A − 1 
Step-by-step explanation:Well we know that for two angles A , B 
it holds that cos ( A + B ) = cos A cos B − sin A ⋅ sin B hence for A = B you get cos ( 2 A ) = cos 2 A − sin 2 A But sin 2 A = 1 − cos 2 A
 
        
                    
             
        
        
        
Answer:
-6x-5
Step-by-step explanation:
remove the parentheses
collect the like terms (-x and -5x, -3 and -2)
evaluate
 
        
             
        
        
        
Answer:
11.7916666667
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
28
Step-by-step explanation:
 
        
             
        
        
        
To solve this, you need to isolate/get the variable "m" by itself in the equation:
1. 2m - 1 = 3m    Subtract 2m on both sides to get "m" on one side of the equation
2m - 2m - 1 = 3m - 2m
-1 = m
2. 2m = 1 + m     Subtract m on both sides to get "m" on one side of the equation
2m - m = 1 + m - m
m = 1
3. m - 1 = 2       Add 1 on both sides to get "m" by itself
m - 1 + 1 = 2 + 1
m = 3
4. 2 + m = 3    Subtract 2 on both sides to get "m" by itself
m = 1
5. -2 + m = 1      Add 2 on both sides to get "m" by itself
m = 3
6. 3 = 1 + m     Subtract 1 on both sides to get "m" by itself
2 = m