Trigonometry is the study of relationships between the sides and angles of a triangle.


sinA = cosA = tanA = BC AC BC AB AB AC A B C Perpendicular Base sinB = cosB = tanB = AC BC AC AB AB BC Base Perpendicular Hypotenuse

The trigonometric ratios of the angle A in right triangle ABC (see Fig.) are defined as follows :
sine of ∠ A = ${side- opposite- to -angle- A(P)}/{hypotenuse(H)}$ = ${BC}/{AB}$

cosine of ∠ A =${side -adjacent- to- angle- A (B)}/{hypotenuse(H)}$=${AC}/{AB}$

tangent of ∠ A =${side- opposite- to- angle- A (P)}/{side- adjacent- to- angle- A(B)}$ =${BC}/{AC}$

cosecant of ∠ A =$1/{sine- of- ∠A }$=${hypotenuse(H)}/{side- opposite -to- angle- A(P)}$=${AB}/{AC}$

secant of ∠ A = $1/{cosine- of - ∠ A}$ = ${hypotenuse(H)}/{side -adjacent- to- angle- A (B)}$ = ${AB}/{AB}$

cotangent of ∠ A = $ 1 /{tangent of ∠ A} $ = ${side -adjacent -to -angle -A(B) }/{side -opposite- to- angle -A(P)}$ =${AC}/{BC}$