1. Sin 70 degrees cos 40 degrees - cos 70 degrees sin 40 degrees

2. cos^-1

3. Solve cos2A=0 on the interval 0 is less than or equal to A which is less than or equal to 2pi?

4. A=35 degrees and side a=5

5. Side a=3 and side b=1

PLEASE SOLVE THESE HARD QUESTIONS FOR ME don't just give the answers!!

1. sin 70 degrees cos 40 degrees - cos 70 degrees sin 40 degrees


Hint: recall the identity for sin(a-b).


2. cos^-1


It appears you left part of the question out.


3. Solve cos2A=0 on the interval 0 is less than or equal to A which is less than or equal to 2pi?

Hint = think about under what conditions cos(x) = 0. For example, cos(\pi) = 0, so 2A = \pi is one solution. There are many more.



4. A=35 degrees and side a=5

5. Side a=3 and side b=1

Presumably there is a picture that goes with these.