👉 Learn how to find a missing angle of a right triangle. A right triangle is a triangle that has 90 degrees as one of its ...

👉 Learn how to evaluate the cosine of an angle in radians using the sum/difference formulas. To do this, we first express the given angle as a sum or a difference of two (easy to evaluate) angles, ...

There are two versions of the cosine rule: Find an unknown side using 𝑎² = 𝑏² + 𝑐² – 2𝑏𝑐 cos𝐴 Find an unknown angle using cos𝐴 = \(\frac{𝑏² + 𝑐² – 𝑎²}{2𝑏𝑐}\) Scientific calculators need to ...

Some exact trigonometric values are equivalent. For example, \( \frac{1}{√2}\) = \( \frac{√2}{2}\). The denominator has been rationalised. To be successful with exact trigonometric values, especially ...