If sin α= P and tan α= Q, find the value of 1P2−1Q2 ?
Option (b)
Assume a 45-45-90 triangle
sin α= P = 1√2 . (Sin= opposite side/ hypotenuse)
tan α= Q = 1 (Tan = opposite side/ adjacent side)
1P2−1Q2 = 2-1 =1
Shortcut
cosec2α – cot2α = 1 is a trigonometric identity
If you are not aware of this identity, substitute α = 45.