CLASS-10
TRIGONOMETRY -TRIGONOMETRICAL RATIOS
TRIGONOMETRICAL RATIOS (T – Ratios) –
Let A be an acute angle of a right △ABC in which ∠B = 90⁰.
Then, Base = AB, Perpendicular = BC, and Hypotenuse = AC
For acute ∠A, we define ;
Perpendicular BC
(i) sine A = ---------------- => sin A = -------
Hypotenuse AC
Base AB
(ii) cosine A = ------------- => cos A = --------
Hypotenuse AC
Perpendicular BC
(iii) tangent A = --------------- => tan A = -------
Base AB
Base AB
(iv) cotangent A = -------------- => cot A = -------
Perpendicular BC
Hypotenuse AC
(v) secant A = -------------- => sec A = -------
Base AB
Hypotenuse AC
(vi) cosecant A = -------------- => cosec A = --------
Perpendicular BC
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