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Determine the value of cos(π/4) using the unit circle

Determine the value of cos(π/4) using the unit circle

To determine the value of $\cos(\frac{\pi}{4})$, we use the unit circle. At the angle $\frac{\pi}{4}$, the coordinates on the unit circle are $(\frac{\sqrt{2}}{2}, \frac{\sqrt{2}}{2})$.

Since the x-coordinate represents the cosine value, we have:

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

Find the values of sin(π/3), cos(π/3), and tan(π/3)

Find the values of sin(π/3), cos(π/3), and tan(π/3)

To find the values of $\sin(\frac{\pi}{3})$, $\cos(\frac{\pi}{3})$, and $\tan(\frac{\pi}{3})$, we use the unit circle.

For $\theta = \frac{\pi}{3}$:

$$ \sin(\frac{\pi}{3}) = \frac{\sqrt{3}}{2} $$

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

$$ \tan(\frac{\pi}{3}) = \frac{\sin(\frac{\pi}{3})}{\cos(\frac{\pi}{3})} = \frac{\frac{\sqrt{3}}{2}}{\frac{1}{2}} = \sqrt{3} $$

Calculate the integral of 1/(1 + x^2) over the unit circle

Calculate the integral of 1/(1 + x^2) over the unit circle

To calculate the integral of $ \frac{1}{1 + x^2} $ over the unit circle, we first convert to polar coordinates:

$$ x = r \cos(\theta), y = r \sin(\theta) $$

In polar coordinates, the unit circle is defined as:

$$ r = 1 $$

Substituting in the integral:

$$ \int_0^{2\pi} \frac{r}{1 + r^2 \cos^2(\theta)} d\theta $$

Since $r = 1$:

$$ \int_0^{2\pi} \frac{1}{1 + \cos^2(\theta)} d\theta $$

Applying the Weierstrass substitution:

Let $ \tan(\theta/2) = t $, then $ d\theta = \frac{2}{1+t^2} dt $

The integral becomes:

$$ \int_{-\infty}^{\infty} \frac{2}{1 + \cos^2(2 \arctan(t))} \frac{1}{1+t^2} dt $$

After simplification, the integral reduces to:

$$ \pi \int_{-\infty}^{\infty} \frac{2}{2 + t^2} \frac{1}{1+t^2} dt $$

The final answer is:

$$ \pi \ln{2} $$

Determine the cosine and sine values at π/4 on the unit circle

Determine the cosine and sine values at π/4 on the unit circle

To find the cosine and sine values at $ \frac{\pi}{4} $ on the unit circle:

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

The values are:

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

Determine the value of cos(θ) and sin(θ) for θ=π/4 on the unit circle

Determine the value of cos(θ) and sin(θ) for θ=π/4 on the unit circle

To determine the values of $\cos(\theta)$ and $\sin(\theta)$ for $\theta=\frac{\pi}{4}$ on the unit circle, we use the known coordinates:

At $\theta=\frac{\pi}{4}$, both cosine and sine values are equal to:

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

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

Therefore, the values are:

$$\cos\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}, \sin\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}$$

Determine the value of cos(θ) and sin(θ) for θ = π/4

Determine the value of cos(θ) and sin(θ) for θ = π/4

To find the values of $ \cos(\theta) $ and $ \sin(\theta) $ when $ \theta = \frac{\pi}{4} $, we use the unit circle.

On the unit circle, when $ \theta = \frac{\pi}{4} $, both $ \cos(\theta) $ and $ \sin(\theta) $ are equal to:

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

Find the value of cos(π/3) and sin(π/3)

Find the value of cos(π/3) and sin(π/3)

To find the value of $ \cos(\frac{\pi}{3}) $, we look at the coordinates of the corresponding point on the unit circle.

The coordinate point at $ \frac{\pi}{3} $ is $ (\frac{1}{2}, \frac{\sqrt{3}}{2}) $.

Hence, $ \cos(\frac{\pi}{3}) = \frac{1}{2} $ and $ \sin(\frac{\pi}{3}) = \frac{\sqrt{3}}{2} $.

Calculate the value of sin(2θ) if cos(θ) = 3/5 and θ is in the first quadrant

Calculate the value of sin(2θ) if cos(θ) = 3/5 and θ is in the first quadrant

To find the value of $ \sin(2\theta) $, we use the double angle identity for sine:

$$ \sin(2\theta) = 2 \sin(\theta) \cos(\theta) $$

Given that $ \cos(\theta) = \frac{3}{5} $, we need to find $ \sin(\theta) $. Since $ \theta $ is in the first quadrant, $ \sin(\theta) $ is positive:

$$ \sin(\theta) = \sqrt{1 – \cos^2(\theta)} = \sqrt{1 – \left(\frac{3}{5}\right)^2} = \sqrt{1 – \frac{9}{25}} = \sqrt{\frac{16}{25}} = \frac{4}{5} $$

Now we can find $ \sin(2\theta) $:

$$ \sin(2\theta) = 2 \cdot \frac{4}{5} \cdot \frac{3}{5} = 2 \cdot \frac{12}{25} = \frac{24}{25} $$

Find the angle on the unit circle corresponding to arctan(1/√3)

Find the angle on the unit circle corresponding to arctan(1/√3)

Given $ \arctan\left(\frac{1}{\sqrt{3}}\right) $, we need to determine the angle $ \theta $ on the unit circle.

We know that $ \arctan(x) $ gives the angle whose tangent is $ x $. Hence:

$$ \tan(\theta) = \frac{1}{\sqrt{3}} $$

We recognize that the angle corresponding to this tangent value is:

$$ \theta = \frac{\pi}{6} $$

Thus, the angle on the unit circle is $ \frac{\pi}{6} $.

Find the cosine of pi/3 using the unit circle

Find the cosine of pi/3 using the unit circle

Using the unit circle, the angle $ \frac{\pi}{3} $ corresponds to 60 degrees. On the unit circle, the coordinates of this angle are:

$$ \left( \frac{1}{2}, \frac{\sqrt{3}}{2} \right) $$

The cosine value is the x-coordinate:

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

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