<PRE><B>Question 1101887</B>
your angle is pi/2.


all angles that are coterminous to this angle will be either 2 * pi degrees more than it or 2 * pi degrees less than it.


since 2 * pi is equal to 4 * pi / 2, then:


pi/2 minus 4 * pi/2 is equal to -3 * pi/2.


-3 * pi/2 minus 4 * pi/2 is equal to -7 * pi/2.


two negative angles coterminous with pi/2 would be -3pi/2 and -7pi/2


you can go on forever.


every angle that is 4pi/2 less than the previous angle will be coterminous with pi/2.


in degrees, every angle that is 360 degrees less than the angle will be coterminous with the angle.


pi/2 radians is equal to 90 degrees.


subtract 360 from that and the first negative coterminous angle would be 90 - 360 = -270.


subtract 360 from -270 and the next negative coterminous angle would be -270 - 360 = -630 degrees.


to convert degrees to radians, multiply the angle in degrees by pi / 180 and you will get the equivalent angle in radians.


90 degrees * pi / 180 is equal to pi/2 radians.


-270 degrees * pi/180 is equal to -3pi/2 radians.


-630 degrees * pi/280 is equal to -7pi/2 radians.


looking at the unit circles, it would look like this.


&lt;img src = &quot;http://theo.x10hosting.com/2017/111801.jpg&quot; alt=&quot;$$$&quot;&gt;


an angle of pi/2 radians is the vertical line going up on the graph.


subtract 2pi from that and the coterminous angle is equal to -3pi/2.


subtract 4pi/2 from that and the coterminous angle is equal to -7pi/2.


subtract 4pi/2 from that and the coterminous angle is equal to -11pi/2.


this can go on forever.


more coterminous angles are 4pi/2 radians less than the previous angle.


you go to -15pi/2, -19pi/2, -23pi/2, ..... forever.


all of these angles are coterminous with pi/2.


the actual formula would be:


coterminous angle to pi/2 = pi/2 plus or minus n * 2pi, where n is a positive integer.


this can also be written as:


coterminous angle to pi/2 = pi/2 plus or minus n * 4pi/2, where n is a positive integer.


-3pi/2 is equal to pi/2 minus 1 * 4pi/2.


-7pi/2 is equal to pi/2 minus 2 * 4pi/2.


-11pi/2 is equal to pi/2 minus 3 * 4pi/2.


etc .....


in degrees, the coterminous angle to 90 is equal to 90 plus or minus n * 360.


-270 is equal to 90 minus 1 * 360.


-630 is equal to 90 minus 2 * 360.


-990 is equal to 90 minus 3 * 360.


etc ...


</PRE>