Trigonometry

Trigonometry (= measurement of triangles) has traditionally been a very important tool for navigators. The relationships between the angles and side lengths of triangles enable the position of a ship to be calculated relative to fixed objects such as lighthouses.  The main ratios are the sine, cosine and tangent of an angle. You can find actual values of these ratios in table books or on your calculator.

• Give the value of each of the following, and then check your answer with a calculator.

sin 45° ; tan 45° ; sin 90° ; cos 60° ; sin 30° .

• Can you simplify the following expressions?

sin / cos ; sin² + cos² ; 1 + tan²

Check