Find the general solution of each of the following equations:
(i) $\sin x=\frac{\sqrt{3}}{2}$
(ii) $\cos x=1$
(iii) $\sec \mathrm{x}=\sqrt{2}$
To Find: General solution.
(i) Given: $\sin x=\frac{\sqrt{3}}{2}$
Formula used: $\sin \theta=\sin \alpha \Rightarrow \theta=\mathrm{n} \pi+(-1)^{\mathrm{n}} \alpha, \mathrm{n} \in$ ।
By using above formula, we have
$\sin x=\frac{\sqrt{3}}{2}=\sin \frac{\pi}{3} \Longrightarrow x=n \pi+(-1)^{n} \cdot \frac{\pi}{3}$
So general solution is $x=n \pi+(-1)^{n} \cdot \frac{\pi}{3}$ where $n \in I$
(ii) Given: $\cos x=1$
Formula used: $\cos \theta=\cos \alpha \Rightarrow \theta=2 n \pi \pm \alpha, n \in I$
By using above formula, we have
$\cos x=1=\cos \left(0^{\circ}\right) \Rightarrow x=2 n \pi, n \in 1$
So general solution is $x=2 n \pi$ where $n \in I$
(iii) Given: $\sec x=\sqrt{2}$
We know that $\sec \theta \times \cos \theta=1$
So $\cos x=\frac{1}{\sqrt{2}}$
Formula used: $\cos \theta=\cos \alpha \Rightarrow \theta=2 n \pi \pm \alpha, n \in I$
So general solution is $x=2 n \pi \pm \frac{\pi}{4}$ where $n \in I$