use the fact that there are 2pi radians in each circle to find another angle,smaller than 2pi,that is equivalent to 13pi/4

[tex]\dfrac{13\pi}4\equiv\dfrac\pi4\mod2\pi[/tex]

Or, put another way, since [tex]\dfrac{13\pi}4=2\pi+\dfrac\pi4[/tex], it follows that [tex]\dfrac\pi4[/tex] is an equivalent angle.

Answer Link

AlonsoDehner AlonsoDehner · Answer 2 · 2019-07-30T10:47:31+02:00

AlonsoDehner AlonsoDehner

30-07-2019

Answer:

Step-by-step explanation:

Given is an angle [tex]\frac{13\pi}{4}[/tex]

We know that there are 2pi radians in each circle

Hence after crossing 2pi radians, the values repeat

[tex]\frac{13\pi}{4}=2\pi+\frac{5\pi}{4}[/tex]

Hence equivalent angle is

[tex]\frac{5\pi}{4}[/tex]

i.e. in the III quadrant making pi/4 with negative x axis.

Answer Link