Q2 of 54 Page 312

Without using trigonometric tables, prove that:
sin248o + sin242° = 1

Consider sin2 48° + sin2 42° = sin2 48° + sin2 (90 - 48)°

= sin2 48° + cos2 48°


= 1


(∵cos2θ + sin2 θ = 1 )


Hence, proved.


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