how do i find sinpi/2 without using a calculator

Question

anonymous · Answer

Here is a unit circle. memorize this as you will use this all through your math career. http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Unit_circle_angles_color.svg/720px-Unit_circle_angles_color.svg.png&imgrefurl=http://en.wikipedia.org/wiki/Unit_circle&h=225&w=225&tbnid=NHFRVspjd-vZrM:&zoom=1&tbnh=186&tbnw=186&usg=__sOrTVeIoKl48_TodEan8dIx7UGk=&docid=D09vYD7H2hKF-M&itg=1&sa=X&ei=juZKU-W1NOjA2gWp44HgDA&ved=0CIkBEPwdMAo

phi · Answer

People memorize the sin, cos and tan of certain angles.   pi/2 (i.e. 90º) is one of them

anonymous · Answer

i used my calculator and got 1? i still dont know how 1 is the answer

anonymous · Answer

the sine of an angle can be considered the y value on the unit circle of that angle. Pi over two is 90 degrees, which is straight upwards. If you go straight upwards on a circle with radius of 1, the answer must be 1.

anonymous · Answer

ok thanks