Answer:
see explanation
Step-by-step explanation:
Using the double angle identity for sine
sin2x = 2sinxcosx
Consider left side
cos20°cos40°cos80°
= 
(2sin20°cos20°)cos40°cos80°
= 
(2sin40°cos40°)cos80°
= (sin80°cos80° )
= 
(2sin80°cos80° )
= . sin160°
= . sin(180 - 20)°
= . sin20°
= 
= right side , thus proven
Answer:
A = 22.62
Step-by-step explanation:
Remember law of tan
tan = opposite/adjacent
tan (A) = 5/12
A= tan inverse ( 5/12)
A = 22.62
Answer:
C; A singleton set
Step-by-step explanation:
Mathematically, when a number is non-negative; it is either positive or zero
Now, this is because 0 identifies as neither a positive or a negative number
hence, when we find the difference between the two sets, the only number that stands out unmatched is the value 0
What this mean is that we are having a set with a single number result
So we have our answer as {0}
Which is a singleton set
