MCQ
જો $\frac{{\sin A - \sin C}}{{\cos C - \cos A}} = \cot B,$ તો $A,B,C$ એ . . . . . શ્રેણીમાં છે.
- ✓સમાંતર
- Bસમગુણોતર
- Cસ્વરિત
- Dએકપણ નહિ.
==>$\frac{{2\cos \frac{{A + C}}{2}\sin \frac{{A - C}}{2}}}{{2\sin \frac{{A + C}}{2}\sin \frac{{A - C}}{2}}} = \cot B$
$ \Rightarrow \cot \frac{{(A + C)}}{2} = \cot B$
==> $B = \frac{{A + C}}{2}$
Thus $A, B, C$ will be in $A.P.$
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