Class X - Trignometry.
In a Right angle triangle,
Sineθ = perpendicular/hypotenues Sineθ= P/H
Cosθ = base/hypotenues Cosθ=B/H
Tanθ = perpendicular/base Tanθ=P/B
Secθ = hypotenues/base Secθ=H/B
Cosecθ = hypotenues/perpendicular Cosecθ=H/P
Cotθ = base/perpendicular Cotθ=B/P
These are basic 6 trinometry functions.