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
Let your age = X
Now you have 500 - 3x = 278
Subtract 500 from each side:
-3x = -222
Divide both sides by -3:
x = -222 / -3
x = 74
You are 74 years old.
Answer:
Step-by-step explanation:
Solution,
p=-4
If you found my answer useful then please mark me brainliest.
Answer:
A) r=2t
B) 4
t²
C) 4(30)² which will end up being 11310 in²
Step-by-step explanation:
A) If it increases 2 inches every minute, you would take that and put it with the t, aka time.
B) A=r² which will translate into A=(2)²
C) You take the half-hour, which is 30 minutes, and translate that into t then place that into your calculator and get an answer of 11,309.73 and then round up to the whole number
Answer:
4/8 and then 1/2so 1/2 is the final answer
