Class 10 Trigonometry Ex 8.1 (Q1–Q7)| All Examples + Fast Tricks| Bihar Board 2026 | NCERT Solutions

Class 10 Trigonometry Ex 8.1 (Q1–Q7) | All Examples + Fast Tricks | Bihar Board 2026 | NCERT Solutions MATH 10TH    • MATH 10TH 2025-2026   Science 10th    • SCIENCE 10TH 2025-2026   Class 10 (Non-Hindi), Class 8 Hindi (NCERT)    • Class 10 (Non-Hindi), Class 8 Hindi (NCERT...   HISTORY 10TH    • HISTORY 10TH 2025-2026   GEOGRAPHY 10TH    • GEOGRAPHY 10TH 2025-2026   Bihar Board 2026 | Class 10 Maths | Trigonometry Chapter 8 Exercise 8.1: Questions 1–7 Complete Solution (with Examples) कवर किए गए टॉपिक्स • Right‑triangle basics: SOH‑CAH‑TOA, opposite/adjacent/hypotenuse पहचान. • Q1: AB=24, BC=7 (∠B=90°) ⇒ AC via Pythagoras ⇒ sinA, cosA; sinC, cosC. • Q2: Diagram‑based tanP − cotR evaluation (triangle से ratios). • Q3: sinA=3/4 ⇒ cosA, tanA (k‑method + Pythagoras). • Q4: 15·cotA=8 ⇒ sinA, secA (cot=AB/BC, then AC=17k). • Q5: secθ=13/12 ⇒ all other ratios (reciprocal + Pythagoras). • Q6: If cosA=cosB (acute) ⇒ prove A=B (monotonicity of cos in (0,90°)). • Q7: cotθ=7/8 ⇒ evaluate compound fraction + cot²θ; convert to sin/cos for clean simplification. Method Template 1. Triangle बनाकर sides को mark करें. 2) Pythagoras: a²+b²=c² से missing side. 3) Required ratio लिखें: sin=opp/hyp, cos=adj/hyp, tan=opp/adj; reciprocal pairs (cosec, sec, cot). 4) Identities/relations से simplify करें. Fast Tricks • k‑method: given ratio = p/q ⇒ opposite = p·k, adjacent = q·k, hyp = √(p²+q²)·k, फिर सारे ratios निकालें. • cot/sec को पहले sin/cos में बदलें; tan = sin/cos, cot = cos/sin; reciprocal set याद रखें. Time‑Stamps 00:00 Hook—“Q1–Q7 में सबसे common गलती: opposite/adjacent उल्टा!” 00:40 SOH‑CAH‑TOA recap + diagram rules 02:00 Q1 full solve (with Pythagoras) 04:00 Q2 tanP−cotR trick 05:30 Q3–Q4 k‑method walkthrough 08:00 Q5 all ratios from secθ 09:30 Q6 proof idea (acute angles) 10:30 Q7 compound evaluation CTA वीडियो helpful लगे तो Like–Share–Subscribe करें. Ex 8.1 (Q1–Q11) PDF Solutions + Tricks चाहिए? Comment: “TRIGO 8.1 Q1–Q7 PDF” — Reply में लिंक मिलेगा। SEO Tags/Keywords Class 10 Trigonometry Exercise 8.1 Q1 to Q7, NCERT Chapter 8 solutions, sin cos tan ratios, Pythagoras with trigonometry, reciprocal and quotient relations, cot to sin cos, sec to all ratios, Bihar Board 2026 Maths, One‑shot Ex 8.1 Hashtags #BiharBoard #Class10Maths #Trigonometry #Exercise8_1 #NCERT #sin #cos #tan #BSEB2026 #OneShot