1. If sin θ = 3/5 and θ is an acute angle, then cos θ is:
Answer:
Explanation:
Using the Pythagorean identity, cos² θ = 1 – sin² θ. So, cos θ = √(1 – (3/5)²) = 4/5.
2. The value of tan 45° is:
Answer:
Explanation:
tan 45° = sin 45°/cos 45° = 1/√2 ÷ 1/√2 = 1.
3. If cos A = 1/√2, then the value of A is:
Answer:
Explanation:
cos 45° = 1/√2.
4. The reciprocal of cosec θ is:
Answer:
Explanation:
cosec θ is the reciprocal of sin θ.
5. The value of sin²θ + cos²θ is always:
Answer:
Explanation:
This is the fundamental Pythagorean identity in trigonometry.
6. The trigonometric ratio which is independent of θ in the first quadrant is:
Answer:
Explanation:
In the first quadrant, all trigonometric ratios are positive.
7. If tan θ = √3, then the value of sin θ is:
Answer:
Explanation:
For tan θ = √3, θ = 60°. So, sin 60° = √3/2.
8. The value of cos 90° is:
Answer:
Explanation:
cos 90° = 0 as the cosine function represents the x-coordinate on the unit circle.
9. If sin θ = x and cos θ = y, then (x² + y²) equals:
Answer:
Explanation:
Given, sin²θ + cos²θ = 1.
10. The general solution for the equation sin x = 0 is:
Answer:
Explanation:
sin function is zero at integral multiples of π.
11. If sec A = 13/12, then tan A is:
Answer:
Explanation:
tan A = √(sec²A – 1) = 5/13.
12. For which of the following angles, sin and cos have the same value?
Answer:
Explanation:
sin 45° = cos 45° = 1/√2.
13. The period of the function sin(x) is:
Answer:
Explanation:
The function sin(x) repeats after an interval of 2π.
14. Which trigonometric ratio is always positive?
Answer:
Explanation:
sec is positive in the first and fourth quadrants.
15. The maximum value of sin x is:
Answer:
Explanation:
The sine function oscillates between -1 and 1.
16. The value of tan(A + B) in terms of tan A and tan B is:
Answer:
Explanation:
This is the compound angle formula for tan(A + B).
17. If sin θ = a/c, then csc θ is:
Answer:
Explanation:
csc θ is the reciprocal of sin θ.
18. The range of the sine function is:
Answer:
Explanation:
The sine function varies between -1 and 1.
19. If cos θ = 0, then θ is:
Answer:
Explanation:
cos 90° = 0.
20. The trigonometric ratio that represents the length of the side opposite to the angle to the hypotenuse is:
Answer:
Explanation:
Sin θ = Opposite side/Hypotenuse.