If A and B are two angles such that A, B, $\in(0, \pi)$ and they are not supplementary angles such that…

If A and B are two angles such that A, B, $\in(0, \pi)$ and they are not supplementary angles such that $\sin A-\sin B=0$, then
  1. $A-B=\frac{\pi}{3}$
  2. $A-B=\frac{\pi}{2}$
  3. $A=B$
  4. $A \neq B$

Solution

$\sin A-\sin B=0$ $\sin A=\sin B$ and we know that $\sin A=\sin (\pi-A)=\sin B$ $\therefore \mathrm{A}=\mathrm{B}$ or $\pi-\mathrm{A}=\mathrm{B}$ $\therefore \mathrm{A}=\mathrm{B}$ or $\mathrm{A}+\mathrm{B}=\pi$ Since the angles are not supplementary we say $\mathrm{A}=\mathrm{B}$.

Asked in: MHT CET 2020 (19 Oct Shift 1)

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