Hi Sonia! Here are the remaining parts for the question.

Part 1 requires you to use the formula from the list. Note that we cannot write tan (A + B) as tan A + tan B, unlike in algebra where 5 (A + B) = 5A + 5B.

Part 2 requires you to draw out the triangle for reference. Fortunately angle A is acute, so all three trigonometric ratios (sin, cos, tan) have positive values.

For part 3, we cannot tell by one look whether 2A is acute or obtuse, since 0 < A < 90 means 0 < 2A < 180 and cos 2A can be positive or negative. Hence, we cannot draw out the triangle for angle 2A, and instead, we must use the double angle formula to break the angle into an equivalent form involving angle A.