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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Answer:
x = 55
Step-by-step explanation:
Draw a line parallel to the top and bottom parallel lines so this new line goes through the pointed end of x.
Draw another line parallel to the top and bottom lines through the pointy end of 45.
The bottom angle of the line through 45 is 15 degrees (alternate interior angles.
The top angle is 45 - 15 = 30
The bottom angle of the line going to x is 150 degrees. It and the 30 degree angle make 180. 30 + 150 = 180
One final observation The top angle of made by the line going through x is 180 - 25 = 155
What you have now is
155 + 150 + x = 360
305 + x = 360
x = 360 - 305
x = 55
.2= 2/10
now you have to reduce it and it is 1/5
the answer to your question is c. -25
C) r = T + 25.3 because you isolate the r variable