cos(2<em>θ</em>) + sin²(<em>θ</em>) = 0
Half-angle identity:
cos(2<em>θ</em>) + (1 - cos(2<em>θ</em>))/2 = 0
Simplify:
2 cos(2<em>θ</em>) + 1 - cos(2<em>θ</em>) = 0
cos(2<em>θ</em>) = -1
Solve for <em>θ</em> :
2<em>θ</em> = arccos(-1) + 2<em>nπ</em>
2<em>θ</em> = <em>π</em> + 2<em>nπ</em>
<em>θ</em> = <em>π</em>/2 + <em>nπ</em>
where <em>n</em> is any integer.
Answer:
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3x + 4y = 5
<u>-5x - 4y = -11</u>
-2x = -6
-<u>2x</u> = <u>-6</u>
-2 -2
x = 3
3(3) + 4y = 5
9 + 4y = 5
<u> -9 -9</u>
4y = -4
<u>4y</u> = <u>-4</u>
4 4
y = -1
(x, y) = (3, -1)
The answer is C....
Hope this helps
Answer:
BC ≈ 12.6 m
Step-by-step explanation:
Using the tangent ratio in the right triangle
tan31° = 
= 
= 
( multiply both sides by BC )
BC × tan31° = 7.6 ( divide both sides by tan31° )
BC = 
≈ 12.6 m ( to 3 sf )
