Q.define ASTC rule...
Answers
The abbreviation for 'all sin cos tan' rule in trigonometry is ASTC . It can be memorized as "All Students Take Calculus". The first letter of the first word in this phrase is 'A'. This may be taken to indicate that all trigonometric ratios in the first quadrant are positive . The first letter of the second word S indicates that sine and its reciprocal are positive in the 2nd quadrant. The first letter of the third word T indicates that tangent and its reciprocal is positive in the third quadrant. The first letter of the last word C indicates that cosine and its reciprocal are positive in the fourth quadrant.
All sin tan cos rule is all trigonometrical ratios in the first quadrant, only sin (and cosec) in the second quadrant, only tan (and cot) in the third quadrant and only cos (and sec) in the fourth quadrant are positive. Hope it helps Thanks...