Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 2 - No. 14)
What is the inverse function to find the angle when you know the ratio for the sides 'Opposite' and 'Hypotenuse'?
sin⁻¹
cos⁻¹
tan⁻¹
cot⁻¹
Explanation
To find the angle you have to use inverse functions.