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:
2 5/12
Step-by-step explanation:
8 5/6 + 2 3/4 = 8 10/12 + 2 9/12 = 10 19/12 = 10 + 1 7/12 = 11 7/12
13 12/12 - 11 7/12 = 2 5/12
Answer:
c. (5, -2)
Step-by-step explanation:
as we can clearly see, the 4th vertex has to be on the positive side of x.
therefore, all answer options with negative x are out.
(2, -5) is almost at D (-1, 5). that cannot be right for a rectangle.
that leaves only c as right answer.
FYI - how to get this without predefined answer portions ?
the x- difference of B to A is 4 (from -5 to -1). the x-difference from D to C must be the same (4). 1 + 4 = 5.
so, x of D must be 5.
the y- difference of B to A is 3 (from 3 to 6). the y-difference from D to C must be the same (3). -5 + 3 = -2.
so, y of D must be -2.
You take the exponent and move that many places with the number that you get on the opposite side
