ABSTRACT
A diagram representing the point (3, 4) is shown in Fig. 24.2.
From Pythagoras’ theorem, r =√32 +42 =5 (note that −5 has no meaning in this context). By trigonometric ratios, θ = tan−1 43 =53.13◦ or 0.927 rad [note that 53.13◦=53.13×(π /180) rad=0.927 rad]. Hence (3, 4) in Cartesian co-ordinates corresponds to (5, 53.13◦) or (5, 0.927 rad) in polar co-ordinates.
