Student Exploration: Sum and Difference Identities for Sine and Cosine

GIZMOS > Student Exploration: Sum and Difference Identities for Sine and Cosine

Bayside High School, Bayside MATH TRIGONOMET Student Exploration: Sum and Difference Identities for Sine and Cosine Vocabulary: identity Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Use ΔABC (a 45-45-90 triangle) to find the exact value of each expression: A. sin 45° = B. cos 45° = 2. Use ΔDEF (a 30- ...[Show More]

Bayside High School, Bayside
MATH TRIGONOMET
Student Exploration: Sum and Difference Identities for

Sine and Cosine

Vocabulary: identity

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. Use ΔABC (a 45-45-90 triangle) to find the exact value of each expression:

A. sin 45° = B. cos 45° =

2. Use ΔDEF (a 30-60-90 triangle) to find the exact value of each expression:

A. cos 30° =

B. sin 30° =

C. cos 60° =

D. sin 60° =

Gizmo Overview

In the Sum and Difference Identities for Sine and Cosine Gizmo, you will use trigonometric

identities (equations that are true for all values) to find the exact value of a given trigonometric

expression.

Here’s how the Gizmo

looks at first:

The expression for you

to evaluate is here.

The tiles give you four

choices for the next

step. Choose the one

you think is correct and

drag it into the white

area above.

Read your feedback in the Gizmo.

(No feedback is given for correct answers.)

Click Proceed to go to the next step.

Continue until the expression is simplified. Then click New for a new problem to work on.

Click Undo to undo

your last choice.

Click New to go to

a different problem.

1

2

E

D

F

1

1

B

A

C

This study source was downloaded by 100000875661904 from CourseHero.com on 11-27-2023 15:09:10 GMT -06:00

https://www.coursehero.com/file/71944178/SumDiffIdSEpdf/

2019

Activity:

Finding exact

values

Get the Gizmo ready:

 You should see the expression sin 75°. If not, click

Refresh in your browser.

The sum and difference identities you will use in this activity are given below:

Sine Cosine

sin ( + ) = sin  cos  + cos  sin cos ( + ) = cos  cos  – sin  sin 

sin ( – ) = sin  cos  – cos  sin  cos ( – ) = cos  cos  + sin  sin 

1. You should see the problem shown to

the right at the top of the Gizmo.