Homework

Find the sine of the angle θ if θ is π/6 radians on the unit circle

To find the sine of the angle $\theta$ when $\theta = \frac{\pi}{6}$ radians:

Step 1: Locate $\frac{\pi}{6}$ on the unit circle. The angle $\frac{\pi}{6}$ is 30 degrees.

Step 2: Use the definition of sine on the unit circle, which is the y-coordinate of the point where the terminal side of the angle intersects the unit circle.

Step 3: For $\theta = \frac{\pi}{6}$, the coordinates on the unit circle are $(\frac{\sqrt{3}}{2}, \frac{1}{2})$.

Therefore, $\sin(\frac{\pi}{6}) = \frac{1}{2}$.

Finding the Sine of an Angle Using the Unit Circle

Given a point on the unit circle corresponding to an angle of \( \frac{\pi}{6} \) (30°), determine the sine of the angle.

The unit circle has a radius of 1. For an angle of \( \frac{\pi}{6} \), the coordinates are:

$$ \left( \cos \frac{\pi}{6}, \sin \frac{\pi}{6} \right) = \left( \frac{\sqrt{3}}{2}, \frac{1}{2} \right) $$

Therefore, the sine of \( \frac{\pi}{6} \) is:

$$ \sin \frac{\pi}{6} = \frac{1}{2} $$

Find the coordinates of the point on the unit circle corresponding to an angle of $\frac{\pi}{3}$ radians

To find the coordinates of the point on the unit circle at an angle of $\frac{\pi}{3}$ radians, we use the cosine and sine functions.

The coordinates are given by: $$ (\cos(\frac{\pi}{3}), \sin(\frac{\pi}{3})) $$

First, calculate the cosine: $$ \cos(\frac{\pi}{3}) = \frac{1}{2} $$

Next, calculate the sine: $$ \sin(\frac{\pi}{3}) = \frac{\sqrt{3}}{2} $$

Therefore, the coordinates are: $$ \left( \frac{1}{2}, \frac{\sqrt{3}}{2} \right) $$

Find all angles θ in radians on the unit circle where sin(θ) = 1/2 and cos(θ) = -√3/2

To find angles θ where $\sin(\theta) = \frac{1}{2}$ and $\cos(\theta) = -\frac{\sqrt{3}}{2}$, we start by identifying possible angles for each trigonometric condition separately:

From $\sin(\theta) = \frac{1}{2}$, the possible angles are $\theta = \frac{\pi}{6}$ and $\theta = \frac{5\pi}{6}$ in the first and second quadrants.

From $\cos(\theta) = -\frac{\sqrt{3}}{2}$, the possible angles are $\theta = \frac{5\pi}{6}$ and $\theta = \frac{7\pi}{6}$ in the second and third quadrants.

The common angle satisfying both conditions is $\theta = \frac{5\pi}{6}$. Therefore, the solution is:

$$ \boxed{\frac{5\pi}{6}} $$

Find the equation of a unit circle

To find the equation of a unit circle centered at the origin, we need to remember that a unit circle has a radius of 1. The standard form of a circle’s equation is:

$$ (x – h)^2 + (y – k)^2 = r^2 $$

Where (h, k) is the center of the circle and r is the radius. Since the unit circle is centered at the origin (0, 0) and has a radius of 1, we can plug in these values:

$$ (x – 0)^2 + (y – 0)^2 = 1^2 $$

Simplifying this, we get:

$$ x^2 + y^2 = 1 $$

The equation of the unit circle is:

$$ x^2 + y^2 = 1 $$

Find the secant value of angle π/3 on the unit circle

To find the secant value, we first need to know the cosine value of the given angle on the unit circle.

The angle $\frac{\pi}{3}$ corresponds to an angle of $60^\circ$.

On the unit circle, the cosine of $\frac{\pi}{3}$ is $\frac{1}{2}$.

The secant is the reciprocal of the cosine:

$$\sec\left(\frac{\pi}{3}\right) = \frac{1}{\cos\left(\frac{\pi}{3}\right)} = \frac{1}{\frac{1}{2}} = 2$$

Given an angle of 5π/6 radians, find the coordinates of the point on the unit circle corresponding to this angle

Given an angle of $\frac{5\pi}{6}$ radians, we need to find the coordinates of the point on the unit circle corresponding to this angle.

First, note that $\frac{5\pi}{6}$ radians lies in the second quadrant. The reference angle for $\frac{5\pi}{6}$ is $\pi – \frac{5\pi}{6} = \frac{\pi}{6}$.

The coordinates of the point corresponding to $\frac{\pi}{6}$ on the unit circle are $(\cos(\frac{\pi}{6}), \sin(\frac{\pi}{6})) = (\frac{\sqrt{3}}{2}, \frac{1}{2})$.

Since $\frac{5\pi}{6}$ is in the second quadrant, the x-coordinate is negative and the y-coordinate is positive. Thus, the coordinates of the point are $(-\frac{\sqrt{3}}{2}, \frac{1}{2})$.

Find the sine of the given angle on the unit circle

Given the angle $ \theta = 30^{\circ} $, we need to find $ \sin(\theta) $ using the unit circle.

On the unit circle, the coordinates of the point corresponding to $ 30^{\circ} $ are $ \left( \frac{\sqrt{3}}{2}, \frac{1}{2} \right) $. The sine of an angle is the y-coordinate of this point. Therefore,

$$ \sin(30^{\circ}) = \frac{1}{2} $$

Understanding the Unit Circle: An Advanced Problem

To understand the unit circle at an advanced level, consider the problem of determining the exact value of trigonometric functions given a point on the unit circle. Suppose a point $P$ on the unit circle corresponds to an angle $\theta$. Given $P = \left(-\frac{3}{5}, -\frac{4}{5}\right)$, find $\sin \theta$, $\cos \theta$, $\tan \theta$, and the corresponding coordinates for $\theta + 2\pi$.

First, recall that for any point $(x, y)$ on the unit circle:

$$ x = \cos \theta, \quad y = \sin \theta $$

Thus, for $P = \left(-\frac{3}{5}, -\frac{4}{5}\right)$, we have:

$$ \cos \theta = -\frac{3}{5}, \quad \sin \theta = -\frac{4}{5} $$

Next, compute $\tan \theta$:

$$ \tan \theta = \frac{\sin \theta}{\cos \theta} = \frac{-\frac{4}{5}}{-\frac{3}{5}} = \frac{4}{3} $$

Lastly, for the angle $\theta + 2\pi$, the coordinates remain the same since $2\pi$ represents a full rotation around the unit circle:

$$ P_{\theta + 2\pi} = \left(-\frac{3}{5}, -\frac{4}{5}\right) $$

Determine the cosine and sine values for an angle of 45 degrees on the unit circle

To determine the $\cos$ and $\sin$ values for an angle of $45^\circ$ on the unit circle, follow these steps:

1. Convert the angle from degrees to radians: $45^\circ = \frac{\pi}{4}$ radians.

2. On the unit circle, the coordinates of a point corresponding to an angle of $\frac{\pi}{4}$ radians are given by $(\cos(\frac{\pi}{4}), \sin(\frac{\pi}{4}))$.

3. Using trigonometric values, we know:

$$\cos(\frac{\pi}{4}) = \frac{\sqrt{2}}{2}$$

$$\sin(\frac{\pi}{4}) = \frac{\sqrt{2}}{2}$$

Thus, the cosine and sine values for an angle of $45^\circ$ are $\frac{\sqrt{2}}{2}$ and $\frac{\sqrt{2}}{2}$ respectively.