Trigonometry

[Jeff ortis]

I'm really struggling with this questions any help would be much appreciated

 

[R.M.]

Subtraction "undoes" addition; division "undoes" multiplication; a square root "undoes" a 2nd power.
What undoes a trig function?

 

[Dr.Peterson]

I'm really struggling with this questions any help would be much appreciated

Please show your work, including an explanation in words of your thinking, and explicit questions about points you are unsure of.

For the first problem, you can use an inverse function on your calculator to find one angle; do you know how to find the one other angle within 360 degrees that has the same cosine?

The same ideas apply to the other problems, with a little additional work after finding the two angles with the given trig functions.

There are several ways I have seen the idea of the "one other angle" taught, so the more you show of how you have been taught, the closer we can make an answer to what you are expected to do.

 

[Jeff ortis]

Yes, I did cos(40) = 0.766
So in (2) do I have to ÷ 29 by 49 then write the figure Dawn and work on the left hand side ?

 

[Cubist]

Yes, I did cos(40) = 0.766

Well done for finding that, however 40° isn't the only answer. Did you manage to find the other solution? Please re-read @Dr.Peterson's reply...

... do you know how to find the one other angle within 360 degrees that has the same cosine?

The same ideas apply to the other problems, with a little additional work after finding the two angles with the given trig functions.

There are several ways I have seen the idea of the "one other angle" taught, so the more you show of how you have been taught, the closer we can make an answer to what you are expected to do.

Hopefully your teacher will have provided you with a method for finding the other angle, either in your notes or in a textbook. Once we know the method that you're expected to use then we'll be able to help you more effectively.