trigonometry

Q) If sin(A + B) = 1 and cos (A − B) = √3/ 2 ,0° < A, B < 90°, find the measure of angles A and B. [Q 22 – Sample Question Paper – CBSE Board 2026] Ans: Let’s take each of the given values one by one: sin (A + B) = 1 Since […]

  Q) Prove that = cosec A + cot A Q29 B– Sample Question Paper – Set 1 – Maths Standard – CBSE 2026 Ans:  Let’s start from LHS: LHS = = = Let’s consider: cos A = P and ( 1 – sin A) = Q ∴ LHS = To normalize the denominator, let’s multiple

Q) If sin θ + cos θ = √3, then prove that tan θ + cot θ = 1 Q29 A – Sample Question Paper – Set 1 – Maths Standard – CBSE 2026 Ans:  Given: sin θ + cos θ = √3 Step 1: By squaring on both sides, we get: ∴ (sin θ +

Q) Let 2A + B and A + 2B be acute angles such that sin (2A + B) = √3 / 2 and tan (A + 2B) = 1. Find the value of cot (4A – 7B). PYQ: 30 (b) – CBSE 2025 – Code 30 – Series 5 – Set 1 Ans: Let’s start solving

Q) Prove the following trigonometric identity: (1 + cosec A) / (cosec A) = (cos2 A) / (1 – sin A) PYQ: 30 (a) – CBSE 2025 – Code 30 – Series 5 – Set 1 Ans: Let’s start from LHS LHS = (1 + cosec A) / (cosec A) = (1 + (1 / sin

Q)   If sin A = y, then express cos A and tan A in terms of y. PYQ: Q 23(b) – CBSE 2025 – Code 30 – Series 5 – Set 1 Ans:  Given that sin A = y. [Approach: Now, if we need to find cos A in terms of y and once

Q) It is given that sin (A – B) = sin A cos B – cos A sin B. Use it to find the value of sin 15°. PYQ: Q 23(a) – CBSE 2025 – Code 30 – Series 5 – Set 1 Ans:  Step 1: Here, we need to find value of sin 15°.

           Q) If sin A = , find the values of cos A and tan A Ans: [Approach: We can calculate the value of cos A by trigonometric identity of sin2 A + cos2 A = 1, and then calculate tan A = sin A / cos A] Step 1: Since we

Q). Prove that: sin θ/(cot θ + cosec θ) = 2 + sin θ /(cot θ – cosec θ) Ans. Let’s start from LHS: Step 1: LHS = = = = Step 2: We know that sin2 θ + cos2 θ = 1 ∴ sin2 θ = 1 – cos2 θ ∴ LHS = Step