High School Math : High School Math

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #4 : The Unit Circle And Radians

What is \displaystyle \sin(\frac{3\pi}{4})?

Possible Answers:

\displaystyle 1

\displaystyle \frac{\sqrt{2}}{2}

\displaystyle -1

\displaystyle \frac{-\sqrt2}{2}

\displaystyle \frac{1}{2}

Correct answer:

\displaystyle \frac{\sqrt{2}}{2}

Explanation:

Using the unit circle, \displaystyle \sin(\frac{3\pi}{4})=\frac{\sqrt2}{2 }. You can also think of this as the sine of \displaystyle 135^\circ, which would also be \displaystyle \frac{\sqrt2}{2}.

Example Question #1 : Using The Unit Circle

What is \displaystyle \cos (\frac{3\pi}{4})?

Possible Answers:

\displaystyle -\frac{\sqrt2}{2}

\displaystyle \frac{2\sqrt2}{2}

\displaystyle -1

\displaystyle \frac{\sqrt2}{2}

\displaystyle 1

Correct answer:

\displaystyle -\frac{\sqrt2}{2}

Explanation:

Using the unit circle, you can see that the \displaystyle \cos (\frac{3\pi}{4})=-\frac{\sqrt2}{2}. Since the angle is in Qudrant II, sine is positive and cosine is negative.

Example Question #2 : The Unit Circle And Radians

What is \displaystyle \sin(\frac{\pi}{4})?

Possible Answers:

\displaystyle \frac{\sqrt2}{2}

\displaystyle \frac{1}{2}

\displaystyle 1

\displaystyle -\frac{\sqrt2}{2}

\displaystyle -1

Correct answer:

\displaystyle \frac{\sqrt2}{2}

Explanation:

Using the unit circle, \displaystyle \sin(\frac{\pi}{4})=\frac{\sqrt2}{2 }. You can also think of this as the sine of \displaystyle 45^\circ, which would also be \displaystyle \frac{\sqrt2}{2}.

Example Question #21 : Graphing The Sine And Cosine Functions

What is \displaystyle \sin(\pi)?

Possible Answers:

\displaystyle \frac{\sqrt{2}}{2}

\displaystyle \frac{\sqrt{3}}{2}

\displaystyle 0

\displaystyle 1

\displaystyle \frac{1}{2}

Correct answer:

\displaystyle 0

Explanation:

If you examine the unit circle, you'll see that that \displaystyle \sin(\pi)=0

Example Question #22 : Graphing The Sine And Cosine Functions

What is \displaystyle \cos(\pi)?

Possible Answers:

\displaystyle 1

\displaystyle 0

\displaystyle \frac{\sqrt3}{2}

\displaystyle -1

\displaystyle \frac{\sqrt2}{2}

Correct answer:

\displaystyle -1

Explanation:

If you examine the unit circle, you'll see that the value of \displaystyle \cos(\pi)=-1. You can also get this by examining a cosine graph and you'll see it crosses the point \displaystyle (\pi,-1).

Example Question #1 : Understanding Radians And Conversions

What is the value of the angle \displaystyle \frac{3\pi}{2} radians when converted to degrees?

Possible Answers:

\displaystyle 270

\displaystyle -180

\displaystyle 90

\displaystyle -45

\displaystyle 135

Correct answer:

\displaystyle 270

Explanation:

The answer can be found using the conversion of 1 radian equals \displaystyle \frac{180}{\pi} degrees.  Multiplying \displaystyle \frac{3\pi}{2} by this conversion factor gives 270 degrees.

Example Question #11 : The Unit Circle And Radians

A point has Cartesian coordinates \displaystyle (1,3). Rewrite this as an ordered pair in the polar coordinate plane, rounding the coordinates to the nearest hundredth.

Possible Answers:

\displaystyle (2.83, 0.32)

\displaystyle (3.16,0.32)

\displaystyle (3.16,0.80)

\displaystyle (2.83, 1.25)

\displaystyle (3.16,1.25)

Correct answer:

\displaystyle (3.16,1.25)

Explanation:

Set \displaystyle x=1, y=3. Calculate the polar coordinates \displaystyle (r,\theta ) as follows:

\displaystyle r = \sqrt{x^{2}+y^{2}}= \sqrt{1^{2}+3^{2}}=\sqrt{10} \approx 3.16

\displaystyle \theta = \arctan \frac{y}{x}= \arctan \frac{3}{1} = \arctan 3 \approx 1.25

Example Question #34 : Trigonometry

How many degrees are in \displaystyle \frac{\pi}{6} radians?

Possible Answers:

\displaystyle 45^\circ

\displaystyle 120^\circ

\displaystyle 360^\circ

\displaystyle 30^\circ

\displaystyle 60^\circ

Correct answer:

\displaystyle 30^\circ

Explanation:

\displaystyle \frac{x^\circ}{\frac{\pi}{6}}=\frac{180^\circ}{\pi}

Cross multiply:

\displaystyle x^\circ*\pi=180^\circ*\frac{\pi}{6}

Notice that the \displaystyle \pi's cancel out:

\displaystyle x^\circ=180^\circ*\frac{1}{6}

\displaystyle x^\circ=30^\circ

Example Question #2 : Understanding Radians And Conversions

How many radians are in \displaystyle 180^\circ?

Possible Answers:

\displaystyle 4\pi

\displaystyle \frac{\pi}{2}

\displaystyle 2\pi

\displaystyle \pi

\displaystyle 3\pi

Correct answer:

\displaystyle \pi

Explanation:

The relationship between degrees and radians is \displaystyle 180^\circ=\pi radians. Therefore, \displaystyle 180^\circ would be \displaystyle \pi radians.

Example Question #3 : Understanding Radians And Conversions

Express in radians: \displaystyle 125^{\circ }

Possible Answers:

\displaystyle \frac{2\pi }{3}

\displaystyle \frac{11\pi }{18}

\displaystyle \frac{15\pi }{36}

\displaystyle \frac{25\pi }{36}

\displaystyle \frac{5\pi }{9}

Correct answer:

\displaystyle \frac{25\pi }{36}

Explanation:

Since \displaystyle 180 ^{\circ } = \pi \textrm{ rad}, we can convert as follows:

\displaystyle 125 \cdot \frac{\pi }{180} = \frac{25\pi }{36}

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