alleryIf cos x = -3/5 and x lies in the THIRD quadrant, then sin x equals:
A-4/5
B+3/4
C-3/4
D+4/5
Answer & Solution
Correct answer: A. -4/5
We have sin²x = 1 - cos²x.
That is sin²x = 1 - 9/25.
So sin²x = 16/25.
→ sin x = ±4/5. In Quadrant III, sin x is negative, so sin x = -4/5.
Keep practising Unit 1A3: Function Composition and Inverses
Browse all Unit 1A3: Function Composition and Inverses questions for AP Calculus AB, or explore more Mathematics topics.
Related questions
How many PERFECT SQUARES lie strictly between 100 and 200?Using prime factorisation, √324 equals:The sum 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 equals:Which of the following is a perfect square?Which of the following is NOT a perfect square?Three rational numbers a, b, c are given. Which of the following is ALWAYS true?For which rational number a is the statement 'a is its own additive inverse' TRUE?Using distributivity, the value of (7/5) × (−3/12) + (7/5) × (5/12) is: