For more cool math videos visit my site at http://mathgotserved.com or http://youtube.com/mathsgotserved

Good students. welcome to part 4 of the sum and difference identities. We're going to be going over one example. So lets go ahead and write down the question. Example 1. Find Sin A minus B Given that Sin A equals 7 over 8 with pie over 2 is less than A. and A is less Than pie. and Cos B equals 6 over 7 with a negative pie over two is less than B And B is less than zero. Alright so lets go ahead and find this. the first thing we are going to do is write down the formula for the difference identities of Sin. So we have Sin A - B equals Sin A Cos B. If the trig functions are different then the sign will stay the same as this one. Minus Cos A Sin B. So lets see what we know. We were provided with Sin A. So we have Sin A we are also provided with Sin B. So in order for us to find Sin A minus B, We need to determine what Sin A is. and what Sin B is. So in order to do that we need to make use of the Path and identity which is Sin Squared theta plus Cos squared Theta equal 1. I know that from this identity ill end up with Sin theta is equal to plus of minus the square root of 1 minus Cos squared theta. This is one variation of the Pythagoras and identity when solving explicitly for Sin. And also know that Cos theta equals plus or minus the square root of one minus Sin squared theta. So this is going to tell me that with Cos i can find Sin and with this one it tells me you can find Sin with Cos. So lets find the component or ingredients that we need to generate Sin A minus B The first thing we need, lets look for Cos A. So we know that Sin A equals 7 over 8 so, Cos A is going to be plus or minus the square root of one minus Sin squared A. We were using this formula while we were replacing the thetas from A. we're going to plug in the value of Cos A which is 7 over 8. so we're going to have Co

Tagged under: classroom,101,instructional,video,lecture,bright,jmt,storm,khanacademy,free,power,polynomials,algebra,guide,tutor,tutorial,tips,trick,-,test,scores,mathtv,mathchannel,prep,college,shortcut,key,ideas,math,mathematicas,cool,doctor,clinic,maths,mathematics,secrets,Guide,Answers,Tricks,Questions,Study,cheat,Algebra,placement,lessons

Clip makes it super easy to turn any public video into a formative assessment activity in your classroom.

Add multiple choice quizzes, questions and browse hundreds of approved, video lesson ideas for Clip

Make YouTube one of your teaching aids - Works perfectly with lesson micro-teaching plans

1. Students enter a simple code

2. You play the video

3. The students comment

4. You review and reflect

* Whiteboard required for teacher-paced activities

With four apps, each designed around existing classroom activities, Spiral gives you the power to do formative assessment with anything you teach.

Quickfire

Carry out a quickfire formative assessment to see what the whole class is thinking

Discuss

Create interactive presentations to spark creativity in class

Team Up

Student teams can create and share collaborative presentations from linked devices

Clip

Turn any public video into a live chat with questions and quizzes

Tried out the canvas response option on @SpiralEducation & it's so awesome! Add text or drawings AND annotate an image! #R10tech

Using @SpiralEducation in class for math review. Student approved! Thumbs up! Thanks.

Absolutely amazing collaboration from year 10 today. 100% engagement and constant smiles from all #lovetsla #spiral

Students show better Interpersonal Writing skills than Speaking via @SpiralEducation Great #data #langchat folks!

Dr Ayla Göl
@iladylayla

A good tool for supporting active #learning.

The Team Up app is unlike anything I have ever seen. You left NOTHING out! So impressed!