Step-by-step explanation:
note that
sin²x = (1-cos²x)
LHS= cos²x - 2 sin²x
= cos²x - 2(1-cos²x)
= cos²x - 2 + 2cos²x
= 3cos²x - 2
or
cos²x = (1-sin²x)
LHS= cos²x - 2 sin²x
=1-sin²x - 2 sin²x
= 1-3sin²x
Answer:
27 tiles
Step-by-step explanation:
First, find the total area of the kitchen.
Use the area formula, A = lw
A = lw
A = (9)(12)
A = 108
So, the area of the kitchen is 108 sq ft
Find the area of the square tiles, using the same formula:
A = lw
A = (2)(2)
A = 4
So, the area of one square tile is 4 sq ft
Find how many tiles they will need to buy by dividing the total area by the area of one tile:
108/4
= 27
So, they will need to buy 27 tiles
The answer to this question is B. I hope this helps