Scalar Product - Example : ExamSolutions

Example question on scalar product.

[skyleonidas]

My math teacher does not know this topic and does not know how to teach it, i don't know what i would have done without this
Thank you

[antoinable]

Thank you very much for all your tutorials!!I'm a french maths teacher and since October I'm also teaching maths in lessons are very clear and interesting ;it helps me a lot to improve my English!

[helenday]

I didn't understand a word of this in my text book. But this video has made all this complex, difficult stuff wonderfully clear. I'm so grateful.

[al-anoud-]

your sketches really help to understand the questions :)

thank you so much

[ExamSolutions_Maths]

Yes of course you can do that. Quite often there is more than one method of answering a question. However, this tutorial was aimed at the scalar product not the cosine rule. I would still encourage you to learn this though as you will need it.

[archjanasivasuthan]

Hi! Thank you for this video. I really appreciate the time and effort you put into all of them. Also, I was wandering if this is on the new spec (scalar vectors/the dot product), please?

[ExamSolutions_Maths]

A pstion or always starts from the origin and will have the same values as the coordinate. (see my earlier tutorial on position vectors)

[shatzE]

ahhh thanks for the advice. You are so much better then my £15K maths teacher

[shatzE]

With all due respect sir, not it be much easier IF we worked out each of the length of the triangle, i.e. AB, AC & BC using the distance equation and then to just use the cosine rule to work out the angle you want?

I have been use that method for all the questions in my edexcel c4 book and i still get the same answer as the book lol

[ExamSolutions_Maths]

Because we are working in degrees not radians so your calculator needs to be in degrees mode.

[TheProblemProduction]

How come you didn't take the answer from 180?If you extrapolate the lines you can see that there are two acute angles and two obtuse angles around angle ABC, so I would've thought that you would've had to subtract from 180?

[Ventsi]

Why cant you just use A and C why do you need to do BA and BC??