Question

sin(a+b)=sin a cos b - cos a sin b for all values of a and b.

true or false?

Answer 1

Why don't you test it for some value a and some value b and see if both sides hold

Answer 2

False

Answer 3

sin(a+b)= sinAcosB+cosAsinB

Answer 4

See what you get on both sides if you let
\[a=\frac{\pi}{2}, b=\frac{\pi}{3}\]
You should get a counterexample out of this

Answer 5

false i think...

Answer 6

\[\sin(\frac{5 pi}{6})=? \sin(\frac{\pi}{2})\cos(\frac{\pi}{3})-\cos(\frac{\pi}{2})\sin(\frac{\pi}{2})\]
\[\frac{1}{2} =? -1 \cdot \frac{1}{2}-0=\frac{-1}{2} \text{ \not equal}\]

Answer 7

Therefore the conclusion is it is not equal for all values a and b

Answer 8

So the statement you have above is false