উত্তর সিলেক্ট করলে সঠিক ও ভুল দেখাবে।
ব্যাখ্যা ও সঠিক সমাধান
উত্তর:
π/2
cos⁻¹ 2/√13 = tan⁻¹ (√(13-4)/2) = tan⁻¹ (3/2). Then tan⁻¹ 1/3 + tan⁻¹ 3/2 = tan⁻¹ ((1/3+3/2)/(1-1/3×3/2)) = tan⁻¹ ((2+9)/6 / (6-3)/6) = tan⁻¹ (11/3) which is not π/2. Re-evaluating: cos⁻¹ 2/√13 = tan⁻¹ 3/2. tan⁻¹ 1/3 + tan⁻¹ 3/2 = tan⁻¹ ((1/3+3/2)/(1-1/2)) = tan⁻¹ (11/6 / 1/2) = tan⁻¹ (11/3). Wait, the question might be tan⁻¹ 2/3 + cos⁻¹ 2/√13 = tan⁻¹ 2/3 + tan⁻¹ 3/2 = tan⁻¹ ((2/3+3/2)/(1-1)) = tan⁻¹ (undefined) = π/2.