3. Reduce 8/10 to 4/5.

7. The inverse of the sin function is the sin^{-1} function.

13. Set up a tangent equation (since you have the two legs but not the hypotenuse) and then take the tangent inverse of each side.

17. Set up a function that involves the hypotenuse.

30. A function is canceled by its inverse, leaving the original argument, such as adding 2 to a number and then subtracting 2 from the result.

31. Why canâ€™t the sine of an angle be 1.2?

33. You can cancel the denominators by multiplying each side by them.