In Fig. 8.13, find tan P – cot R.
Applying Pythagoras theorem for ΔPQR, we obtain
PR2 = PQ2 + QR2
(13 cm)2 = (12 cm)2 + QR2
169 cm2 = 144 cm2 + QR2
25 cm2 = QR2
QR = 5 cm
tan P = 
= 
cot R = 
= 
tan P - cot R = 
= 0
2
In Fig. 8.13, find tan P – cot R.
Applying Pythagoras theorem for ΔPQR, we obtain
PR2 = PQ2 + QR2
(13 cm)2 = (12 cm)2 + QR2
169 cm2 = 144 cm2 + QR2
25 cm2 = QR2
QR = 5 cm
tan P =
=
cot R =
=
tan P - cot R =
= 0