state gov UKPSC Police SI Mock Test 2024 Quantitative Aptitude Trigonometry Trigonometric Ratios and Identities
If A, B, C are interior angles of a triangle and \(\sin \left(\frac{B+C}{2}\right)=\cos (x)\), then x is:
1
A
2
\(\left(\frac{\mathrm{A}}{2}\right)\)
3
(-A)
4
\(\left(\frac{\mathrm{3A}}{2}\right)\)