What is a radian? · A RADIAN is the measure of a central angle that intercepts an arc with the...

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Lesson 6.3 ~ Radian Measure Objectives: I understand the definition of a radian. I can convert between radian and degree measure. I can find the sine and cosine of a radian measure. I can find arc length in radian measure. I can use radian measure to solve real world problems.

Transcript of What is a radian? · A RADIAN is the measure of a central angle that intercepts an arc with the...

Page 1: What is a radian? · A RADIAN is the measure of a central angle that intercepts an arc with the length equal to the radius of the circle. Radians measure the amount of rotation between

Lesson 6.3 ~ Radian Measure

Objectives:

• I understand the definition of a radian. • I can convert between radian and degree measure. • I can find the sine and cosine of a radian measure. • I can find arc length in radian measure. • I can use radian measure to solve real world problems.

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What is a radian?

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How do you remember which fraction to multiply by when converting between radians and degrees?  

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Must show conversion work – we’re practicing here!

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Remember how to find coterminal angles when our angles were in degrees?

How do you think we find coterminal angles when our angles are in radian?

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d

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1

0

Opposite

Adjacent

sin    =  cos    = 

tan    = 

0 0

0

What is tangent & how can we find it on the unit circle?

(Think SOH CAH TOA)

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How could you find the arc length on a circle?

8 in.

L

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Stop and think!  An angle in standard position on a unit circle can have a negative measure.  When calculating the length of an intercepted arc, we take the absolute value of the angle measure?  Why?

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three decimal places.

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three decimal places.

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Assignment:Section 6.3:  problems 8­23, 25, 27, 28

(On #14­17, also state one positive and one negative coterminal angle.  On calculator problems, round to three decimals, not two.)

AND

Trigonometry Unit Circle Monster(Do the monster by memory.  This uses the unit circle we made, 

but you should have the pattern memorized by now.)