cos (2x) = cos x
2 cos^2 x -1 = cos x using the double angle formula
2 cos ^2 x -cos x -1 =0
factor
(2 cos x+1) ( cos x -1) = 0
using the zero product property
2 cos x+1 =0 cos x -1 =0
2 cos x = -1 cos x =1
cos x = -1/2 cos x=1
taking the arccos of each side
arccos cos x = arccos (-1/2) arccos cos x = arccos 1
x = 120 degrees x=-120 degrees x=0
remember you get 2 values ( 2nd and 3rd quadrant)
these are the principal values
now we need to add 360
x = 120+ 360n x=-120+ 360n x = 0 + 360n where n is an integer
3/10 = .3 and 87/100 = .87
382.3 - 191.87= 190.43
so the answer is 190.43
Hope this helped!! :))
Answer: To find the area of a rectangle, multiply its height by its width. For a square you only need to find the length of one of the sides (as each side is the same length) and then multiply this by itself to find the area.
Answer:
The length is 6 feet and the width is 4 feet
Step-by-step explanation:
Let x represent the length of the yard
The width can be represented by x - 2, since it is 2 less than the length.
Use the perimeter formula, P = 2l + 2w, where l is the length and w is width
Plug in the expressions and perimeter:
20 = 2x + 2(x - 2)
Solve for x:
20 = 2x + 2x - 4
20 = 4x - 4
24 = 4x
6 = x
So, the length is 6. Plug this into x - 2 to find the width
x - 2
6 - 2
= 4
So, the length is 6 feet and the width is 4 feet
