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.

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)

I have a question about Question 2)

180<A<360 should be at Quadrant III and IV.

Why you said that is Quadrant II and III ?

looking forward for your reply Thanks