Trig Equations A34C04
1. We are asked to solve the following trigonometric equations for $x$:
(i) $\sin x = \frac{1}{2}$
(ii) $\sin x = -\frac{\sqrt{2}}{2}$
(iii) $\sin x = 0$
(iv) $\sin x = \frac{1}{3}$
(v) $\sin x = -\frac{1}{4}$
(vi) $\cos x = \frac{1}{2}$
(vii) $\cos x = -\frac{\sqrt{3}}{2}$
(viii) $\cos x = -1$
(ix) $\cos x = \frac{1}{3}$
(x) $\cos x = -\frac{1}{4}$
(xi) $\tan x = \sqrt{3}$
(xii) $\tan x = 1$
(xiii) $\tan x = 2$
2. The general solutions for sine, cosine, and tangent equations are:
- For $\sin x = a$, solutions are $x = \arcsin(a) + 2k\pi$ or $x = \pi - \arcsin(a) + 2k\pi$, where $k$ is any integer.
- For $\cos x = a$, solutions are $x = \arccos(a) + 2k\pi$ or $x = -\arccos(a) + 2k\pi$.
- For $\tan x = a$, solutions are $x = \arctan(a) + k\pi$.
3. Now we solve each:
(i) $\sin x = \frac{1}{2}$
$\Rightarrow x = \frac{\pi}{6} + 2k\pi$ or $x = \frac{5\pi}{6} + 2k\pi$
(ii) $\sin x = -\frac{\sqrt{2}}{2}$
$\Rightarrow x = -\frac{\pi}{4} + 2k\pi$ or $x = \pi + \frac{\pi}{4} + 2k\pi = \frac{5\pi}{4} + 2k\pi$
(iii) $\sin x = 0$
$\Rightarrow x = k\pi$
(iv) $\sin x = \frac{1}{3}$
$\Rightarrow x = \arcsin(\frac{1}{3}) + 2k\pi$ or $x = \pi - \arcsin(\frac{1}{3}) + 2k\pi$
(v) $\sin x = -\frac{1}{4}$
$\Rightarrow x = -\arcsin(\frac{1}{4}) + 2k\pi$ or $x = \pi + \arcsin(\frac{1}{4}) + 2k\pi$
(vi) $\cos x = \frac{1}{2}$
$\Rightarrow x = \frac{\pi}{3} + 2k\pi$ or $x = -\frac{\pi}{3} + 2k\pi = \frac{5\pi}{3} + 2k\pi$
(vii) $\cos x = -\frac{\sqrt{3}}{2}$
$\Rightarrow x = \frac{5\pi}{6} + 2k\pi$ or $x = \frac{7\pi}{6} + 2k\pi$
(viii) $\cos x = -1$
$\Rightarrow x = \pi + 2k\pi$
(ix) $\cos x = \frac{1}{3}$
$\Rightarrow x = \arccos(\frac{1}{3}) + 2k\pi$ or $x = -\arccos(\frac{1}{3}) + 2k\pi$
(x) $\cos x = -\frac{1}{4}$
$\Rightarrow x = \arccos(-\frac{1}{4}) + 2k\pi$ or $x = -\arccos(-\frac{1}{4}) + 2k\pi$
(xi) $\tan x = \sqrt{3}$
$\Rightarrow x = \frac{\pi}{3} + k\pi$
(xii) $\tan x = 1$
$\Rightarrow x = \frac{\pi}{4} + k\pi$
(xiii) $\tan x = 2$
$\Rightarrow x = \arctan(2) + k\pi$
4. Here $k$ is any integer representing the periodic nature of trigonometric functions.
This completes the solutions for all given equations.