I'm confused on how to use the diagram to find what is necessary to find the exact values for sin (a+b) , cos (A-B) and tan (A+B)
What happened to negative for Tan B = -3/4 in the diagram?
I had a another quick question to ask if you are required to find the exact value of 135° Would the answer be -cos (45) = 1/square root of 2?
I only just realised i marked my answers correct without knowing what the actual answers were so i wanted check if inwas right or not
The basic idea is to use Pythagoras theorem to find the missing side of the triangles, and then use angle expansion formulae to figure out the answer. Do you learn, for example:
You can find the values of \(\sin{a},\cos{a},\sin{b}\) (etc) by using right angled trigonometry with those diagrams (once you've found the missing side using Pythagoras theorem).
Yep, you're totally right, the bottom side should be -4 in the diagram, not 4, sorry
If you mean the exact value of \(\cos{135}\), then yep!