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Hi! I want to have precision about co-functions in trigonometry. As I know,...
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High School Teacher
So far what you know is correct. So I underatand that you are looking for the angles 270 and 450. Well since 270 is the (-) y-axis you could use your relationships that you understand for 90 which is the (+) y-axis.
Since cos (90-`theta)=sintheta`
then cos (270-`theta)= -sintheta`
then sin(270-`theta)= -costheta`
Since 450 degrees is a coterminal angle for 90 degrees (90+360=450)
Posted by baxthum8 on August 16, 2013 at 10:38 PM (Answer #1)
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