SPM Mathematics Glossary
Ratios and Graphs of Trigonometric Functions, terms
Frequently asked questions
What's the difference between angle of elevation and angle of depression, and why do students mix them up?
Angle of elevation is measured upward from the horizontal when looking at something higher than you; angle of depression is measured downward when looking at something lower. Students confuse them because both are measured from a horizontal line, but drawing that horizontal line at the observer's eye level first makes it clear which angle applies.
Which special angles should I memorise first, and how are sine, cosine and tangent graphs different from each other?
Memorise the sine, cosine and tangent values for 0°, 30°, 45°, 60° and 90° first, since these appear repeatedly without a calculator. The sine and cosine graphs have the same wave shape but are shifted apart, while the tangent graph looks completely different, with repeated breaks where the value is undefined.
How does the term "quadrant" come up in trigonometric graph questions?
Quadrant refers to which of the four regions an angle falls into, and it determines whether sine, cosine or tangent is positive or negative there. Exam questions often ask you to read a value off a graph or state the sign of a ratio for an angle in a given quadrant, so knowing the quadrant rules speeds up your answer.