2cosx=2sin2x. Sin2x is an identity for 2sinxcos. So 2[2sinxcosx] gives you 4sinxcosx. 2cosx=4sinxcosx. Divide 2cosx on both sides and gives you 2sinx=0 and divide again, sinx=0. Sinx is 0 at 0 and 360 degrees, or pi and 2pi. So thats what x would be. 0,360,pi,2pi.
Answer:
807.8 in^2
Step-by-step explanation:
The total area of the box is the sum of the areas of all faces of the box. The top, bottom, front, and back faces are rectangles 18 in long. The end faces each consist of a rectangle and a triangle. We can compute the sum of these like this:
The areas of top, bottom, front, and back add up to be 18 inches wide by the length that is the perimeter of the end: 2·5in +2·8 in + 9.6 in = 35.8 in. That lateral area is ...
(18 in)(35.6 in) = 640.8 in^2
The area of the triangle on each end is equivalent to the area of a rectangle half as high, so we can compute the area of each end as ...
(9.6 in)(8.7 in) = 83.52 in^2
Then the total area is the lateral area plus the area of the two ends:
640.8 in^2 + 2·83.52 in^2 = 807.84 in^2 ≈ 807.8 in^2
Option 1 =$497.5 option 2 =$494.5 option 3 =$50.5
They are not the same thing.
Answer:
3/8ths of 680 kcal or 3 x 85 = 255 kcal.
Step-by-step explanation:
3/8ths of 680 kcal or 3 x 85 = 255 kcal.
