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!!

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Originally Posted by kite9200

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

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

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Originally Posted by kite9200

2. cos^-1

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It appears you left part of the question out.

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Originally Posted by kite9200

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

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

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Originally Posted by kite9200

4. A=35 degrees and side a=5

5. Side a=3 and side b=1

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Presumably there is a picture that goes with these.