Find the length of RA. A. 42 B. 84 C. 14 D. 7
2 answers:
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The cosine of an angle is the x-coordinate of the point where its terminal ray intersects the unit circle. So, we can draw a line at x=-1/2 and see where it intersects the unit circle. That will tell us possible values of θ/2.
We find that vertical line intersects the unit circle at points where the rays make an angle of ±120° with the positive x-axis. If you consider only positive angles, these angles are 120° = 2π/3 radians, or 240° = 4π/3 radians. Since these are values of θ/2, the corresponding values of θ are double these values.
a) The cosine values repeat every 2π, so the general form of the smallest angle will be
... θ = 2(2π/3 + 2kπ) = 4π/3 + 4kπ
b) Similarly, the values repeat for the larger angle every 2π, so the general form of that is
... θ = 2(4π/3 + 2kπ) = 8π/3 + 4kπ
c) Using these expressions with k=0, 1, 2, we get
... θ = {4π/3, 8π/3, 16π/3, 20π/3, 28π/3, 32π/3}
Answer:
Step-by-step explanation:
Let:
This is and exact equation, because:
So, define f(x,y) such that:
The solution will be given by:
Where C1 is an arbitrary constant
Integrate with respect to x in order to find f(x,y):
Where g(y) is an arbitrary function of y.
Differentiate f(x,y) with respect to y in order to find g(y):
Substitute into
Integrate with respect to y:
Substitute g(y) into f(x,y):
The solution is f(x,y)=C1
Solving y using quadratic formula: