The basic angle for 1/2 is 60°, and cosines are negative in the first and third quadrant.
So, you take 180° - 60° = 120° to get the angle in the first quadrant, and 180° + 60° = 240° to get the angle in the third quadrant.
Since only 120° is an option, the answer is
B.
The value of the given trigonometry function is 2√15/15
<h3>Half angles</h3>
Half angles are trigonometric identities used to express sine, cosine and tangent of half angles.
For instance the value of cos theta is expressed as shown below;
cosФ = cos(Ф/2+Ф/2)
cosФ = cos²Ф/2-sin²Ф/2
cosФ = cos²Ф/2-(1-cos²Ф/2)
cosФ = 1 - 2cos²Ф/2
Given the following parameters
cosФ = -7/15
Substitute
cosФ = 1 - 2cos²Ф/2
-7/15 = 1 - 2cos²Ф/2
-2cos²Ф/2 = -7/15 - 1
-2cos²Ф/2 = -8/15
cos²Ф/2 = 4/15
cosФ/2 = 2/√15
Rationalize
2/√15 * √15/√15
2√15/15
Hence the value of the given trigonometry function is 2√15/15
Learn more on trigonometry function here: brainly.com/question/2254074
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Formula
Area = L*w
Hint : To find the area of a rectangle , multiply the length times the width
I hope that's help !
Answer:
7 people, 7 walls, 48 minutes
Each person paints 1 wall in 48 minutes
20 persons, 20 walls
Each person can paint 1 wall in 48 minutes so it will take 48 minutes.
So assuming that youmeans there were 35 MORE rose plants than sunflower seeds, then
Rose:Sunflower =8:3
rose=sunflower+35
therefor
8 units=rose
3 units=sunflowers
rose-35=sunflower
8unit-35=3unit
5unit-35=0
5unit=35
therefor
35=5unit
divide by 5
7=1unit
so 8 units of roses
7 times 8=56
3 units of sunflowers
3 times 7=21
rose=56
sunflower=21
