Question

Arrange the angles in increasing order of their cosines.

Answer 1

Answer:

$\pi,\ \dfrac{7\pi}{6},\ \dfrac{3\pi}{4},\ \dfrac{4\pi}{3},\ \dfrac{3\pi}{2},\ \dfrac{5\pi}{3},\ \dfrac{7\pi}{4},\ 2\pi.$

Step-by-step explanation:

Convert each angle in degree measure:

$\dfrac{3\pi}{4}=135^{\circ},\\ \\\pi=180^{\circ},\\ \\\dfrac{7\pi}{6}=210^{\circ},\\ \\\dfrac{5\pi}{3}=300^{\circ},\\ \\\dfrac{7\pi}{4}=315^{\circ},\\ \\\dfrac{4\pi}{3}=240^{\circ},\\ \\\dfrac{3\pi}{2}=270^{\circ},\\ \\2\pi=360^{\circ}.$

Then

$\cos \dfrac{3\pi}{4}=\cos 135^{\circ}=-\dfrac{\sqrt{2}}{2},\\ \\\cos \pi=\cos 180^{\circ}=-1,\\ \\\cos \dfrac{7\pi}{6}=\cos 210^{\circ}=-\dfrac{\sqrt{3}}{2},\\ \\\cos \dfrac{5\pi}{3}=\cos 300^{\circ}=\dfrac{1}{2},\\ \\\cos \dfrac{7\pi}{4}=\cos 315^{\circ}=\dfrac{\sqrt{2}}{2},\\ \\\cos \dfrac{4\pi}{3}=\cos 240^{\circ}=-\dfrac{1}{2},\\ \\\cos \dfrac{3\pi}{2}=\cos 270^{\circ}=0,\\ \\\cos 2\pi=\cos 360^{\circ}=1.$

Therefore, the angles in increasing order of their cosines are

$\pi,\ \dfrac{7\pi}{6},\ \dfrac{3\pi}{4},\ \dfrac{4\pi}{3},\ \dfrac{3\pi}{2},\ \dfrac{5\pi}{3},\ \dfrac{7\pi}{4},\ 2\pi.$

Answer 2

Answer:

Step-by-step explanation: