Introduction to Trigonometry Class 10 Maths Important Questions
Q 1 – Given that sin α = 1/2 , and cos β = 1/2 , then the value of (α +β)
(a) 0°
(b) 30°
(c) 60°
(d) 90°
Q 2 – If ABC is right angled triangle at C, then the value of cos (A+B)
(a) 0
(b) 1/√3
(c)√3/2
(d) 1
Since the triangle is right-angled at ,
A + B + C = 180º
A + B = 180º – 90º = 90º
Therefore,
cos (A + B) = cos 90º = 0
Q 3 – In ABC, ∠ C= 90, the value of 1 +tan2A
(a) sec2 C
(b) cosec2 B
(c) sec2 B
(d) cosec2 C
Q 4 – 2 tan 30º/1 + tan2 30 ºis equal to
a) sin 60°
(b) cot 30°
(c) tan 60°
(d) 2 /tan 30º
Q 5 – 4 tan2α – 4sec2α
(a) – 4
(b) 4
(c) 2
(d) – 2
Q 6 – If x = 3sin β and y =4 cos β, find the value of 
(a) 12
(b) 15
(c) 20
(d) 5
Q 7 – If 2 cos, find the value of 
(a) 2+√3
(b) 2 – √3
(c) √3
(d) None of these
Q 10 – If sec θ+ tan θ = p, show that
Q 11 – If x = a sin α and y = b tan α , then show that 
Q 12 – What happens to the value of tanθ when θ increases from 0° to 90°?
Q 13 – In ∆ABC right angled at B, AB = 24 cm, BC = 7 cm. Determine
(i) sin A, cos A
(ii) sin C, cos C
Q 14 – In the given figure find tan P – cot R
Q 15 – Given 15 cot A = 8. Find sin A and sec A.
Q 16 – Given sec θ = 13/12 calculate all other trigonometric ratios.
Q 17 – Prove that: (1 + tan A – sec A) (1 + tan A + sec A) = 2 tan A
Q 19 – Assertion The value of sin θ = 4/3 is not possible.
Reason Hypotenuse is the largest side in any right angled triangle.
(a) Both assertion (A) and reason (R) are true and reason
(R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason
(R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Q 26 – In the adjoining figure, what is the length of BC ?
Q 27 – If sec θ sin θ = 0, then find the value of θ.
Q 28 – What happens to value of cos θ when θ increases from 0º to 90º
Q 29 – Find the value of sin2 41 + sin2 49
Q 30 – Evaluate: 
Q 31 – In the given figure, AOB is a diameter of a circle with centre O, find tan A tan B.
Q 32 – Express the trigonometric ratio of sec A and tan A in terms of sin A.
Q 33 – Find the value of tan2 10 – cot2 80.
Q 34 – If A and B are acute angles and sin A= cos B, then find the value of A + B
Q 35 – Find the value of cot 10º cot 30º cot 80