Intro to Sum and Difference Identities

11.3 Angle Sum/Difference Trig Identities

Examples

Multiple Select

With less than 2 weeks left of school,

what can you do to end the year successfully?

• Check Student Self Serve and Canvas to see missing assignments.

• Complete at least an assignment daily.

• Talk to teachers if I need help

• Attend Synchronous meetings

• Binge watch a new show on Netflix

Multiple Choice

Expand $$\sin\ \left(33^{o\ }+42^o\right)$$  

• $$\sin\ 75^{o\ }$$  

• $$\sin\ 33^o\cos42^o+\cos33^o\sin42^o$$  

• $$\sin\ 33^o\cos42^o-\cos33^o\sin42^o$$  

• $$\cos33^o\cos42^o+\sin33^o\sin42^o$$  

Multiple Choice

$$\frac{\tan45^o+\tan30^o}{1-\tan45^o\tan30^o}$$  is equivalent to

• $$\tan75^o$$  

• $$\tan\ 15^o$$  

• $$\frac{\sin45^o}{\cos30^o}$$  

• $$\tan90^{o\ }$$  

Multiple Choice

$$\cos75^o\cos15^o-\sin75^{o\ }\sin15^o$$  is equivalent to

• $$\sin\ 90^{o\ }$$  

• $$\sin\ 60^{o\ }$$  

• $$\cos\ 90^{o\ }$$  

• $$\cos\ 60^{o\ }$$  

Multiple Choice

Given angle A and B in Quadrant I with  $$\sin A\ =\frac{12}{13}\ and\ \cos B\ =\frac{3}{5}\ find\ \cos\left(A+B\right)$$  

(Use SOH CAH TOA to build reference triangle)

• $$-\frac{33}{65}$$  

• $$\frac{33}{65}$$  

• $$\frac{1}{2}$$  

• $$\frac{12}{13}$$  

Multiple Choice

Use sum or difference angles identity to find the exact value for       $$\sin\ \left(-15^o\right)$$  

• $$\frac{\sqrt{6}+\sqrt{2}}{4}$$  

• $$\frac{\sqrt{6}-\sqrt{2}}{4}$$  

• $$\frac{\sqrt{2}-\sqrt{6}}{4}$$  

• $$-\frac{\sqrt{3}}{2}$$  

Remember...

Lilly and Daisy Say:

-Less than 2 Weeks left of school

-Last unit we'll cover is 11.4

-You can still make up 1st semester and 4th / 5th Six Weeks

-Check Canvas + SSS grades to make sure you're caught up.