# Mathematics Questions and Answers – Trigonometric Functions – 1

«
»

This set of Mathematics Multiple Choice Questions & Answers (MCQs) focuses on “Trigonometric Functions – 1”.

1. If sin x=0 then x = ________
a) nπ
b) (2n+1) π/2
c) (n+1) π
d) nπ/2

Explanation: When know, sin x =0 whenever x is 0, π, 2π, 3π,….. i.e. all integral multiples of π so, x=nπ when sin x=0.

2. If cos x=0 then x = ________
a) nπ
b) (2n+1) π/2
c) (n+1) π
d) nπ/2

Explanation: When know, cos x =0 whenever x is π/2, 3π/2, 5π/2, ………… i.e. all odd integral multiples of π/2
so, x=(2n+1) π/2 when cos x=0.

3. If tan x = 0 then x = _________
a) nπ
b) (2n+1) π/2
c) (n+1) π
d) nπ/2

Explanation: We know, tan x = sin x / cos x. So, tan x will be zero wherever sin x is zero except the points where cos x is also zero. We know there is no point where sin x as well as cos x both are zero. So, tan x = 0 => x=nπ.
Sanfoundry Certification Contest of the Month is Live. 100+ Subjects. Participate Now!

4. 1-sin245° = ___________
a) 1/2
b) 1
c) 0
d) √3 /2

Explanation: We know, sin245° + cos245°=1
So, 1- sin245° = cos245° = (1/√2)2 = 1/2.

5. 1-cos2x=_________
a) sin x
b) cos x
c) sin 2x
d) sin2x

Explanation: We know, sin2x+ cos2x=1
So, 1-cos2x=sin2x.

6. 1-sec2x=_________
a) cot2x
b) tan2x
c) -tan2x
d) -cot2x

Explanation: We know, sec2x – tan2x=1
So, 1-sec2x=-tan2x.

7. 1+ tan2x=_______________
a) sec2x
b) -sec2x
c) cosec2x
d) -cosec2x

Explanation: We know, sec2x – tan2x=1
So, 1+ tan2x=sec2x.

8. cot2x – cosec2x = __________
a) 1
b) -1
c) sin2x
d) cos2x

Explanation: We know, cosec2x – cot2x = 1
So, cot2x – cosec2x = -1.

9. cosec2x – 1 = ______________
a) cot2x
b) -cot2x
c) tan2x
d) -tan2x

Explanation: We know, cosec2x – cot2x = 1
So, cosec2x – 1 = cot2x.

10. tan x is not defined for_______
a) 0
b) nπ/2
c) (2n+1) π/2
d) nπ

Explanation: We know, tan x is not defined when cos x = 0.
cos x = 0 whenever x is π/2, 3π/2, 5π/2, ………… i.e. all odd integral multiples of π/2
so, x=(2n+1) π/2.

11. sin (-45°) = ______________
a) 1
b) -1
c) 1/√2
d) -1/√2

Explanation: We know, sin(-x) = sin x
So, sin (-45°) = -sin 45° = -1/√2.

12. cos (-60°) = ________________
a) -√3/2
b) 1/2
c) √3/2
d) -1/2

Explanation: We know, cos (-x) = cos x
So, cos(-60°) = cos 60°=1/2.

Sanfoundry Global Education & Learning Series – Mathematics – Class 11.

To practice all areas of Mathematics, here is complete set of 1000+ Multiple Choice Questions and Answers.