Recall the half-angle identity:
cos²(x) = 1/2 (1 + cos(2x))
Let x = 75°, so that 2x = 150°. Then
cos²(75°) = 1/2 (1 + cos(150°))
You might already be aware that cos(150°) = -√3/2, so
cos²(75°) = 1/2 (1 - √3/2)
cos²(75°) = 1/2 - √3/4
cos²(75°) = (2 - √3)/4
But this is the square of the number we want, which we solve for by taking the square root of both sides. This introduces a second solution, however:
cos(75°) = ± √[(2 - √3)/4]
cos(75°) = ± √(2 - √3)/2
75° falls between 0° and 90°, and you should know that cos(x) is positive for x between these angles. This means cos(75°) must be positive, so we pick the positive root:
cos(75°) = √(2 - √3)/2
Answer:
i don't know
Step-by-step explanation:
check with someone else
We are asked to define the width and length of a rectangular college athletic field with a parameter of 98 and length 12 more than the width, we represent x as the width, that is the length is x+12. Using parameter formula: 96/2 = x + x+ 12 ; <span>48 = 2x + 12; x is equal to 18 m while x + 12 is equal to 30 m </span>
Answer:
Contrapostitve for Math on APEX.
x=>y
-~y=> -~
*the ~ arent part of the question, i just have no key for square root
Step-by-step explanation:
