Answers

2015-02-09T17:49:44+05:30
You just draw 2 right-angled triangles
1.... the angles =45,45,90
   the opposite side of 45=1
the opposite side of 90=√2
you can understand here cos 45=sin45=1/√2

2.....the angles =30,60,90
the opposite side of 30=1
the opposite side of 60=√3
the opposite side of 90=2
cos 30=sin 60= 1/2
sin 90=1




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