Hey there,

This is the video tutorial to answer a question posted by a student.

Here’s what she asked,

Sabrina
2010/07/10 at 7:19 pm
Hi miss Ng, can you tell me the answer for the questions below:
1) given sin A = 3/5 and sin B= 12/13. A,B-acute angle. find a)sin(A-B) b)cos(A+B) c)tan(A-B)
2)given that tan A=3/4 180<A<360, find a)tan(A+45) b)sin(A+30)
3)given sin x= 8/17, cos= -15/17 , sin y=3/5 and cos y=4/5. Find a) sin(x-y) b)cos(x-y) c)tan(x-y)
thanks in advance.

and here’s the video tutorials to answer the question.

NOTE : I’m now using You Tube to embed my videos here, so you can download or share the videos with your friends :)

You may want to try out another question which uses the Double Angle and Half Angle Formulae here.

Part 1 (question 1)

Part 2 ( Question 2 and 3)