Question

Sin217.5 + Sin272.5 = __________?? Explain...

Answer 1

sin217.5°+sin272.5°
=sin2(90°−72.5°)+sin272.5°
=cos272.5+sin272.5°             
[(sin(90−θ)=cosθ)]
=1

Answer 2

sin^2 17.5° + sin^2 72.5°

= sin^2( 90- 72.5°)+ sin^2 72.5°

= cos^2 72.5° + sin^2 72.5°

= sin(90 - θ)= cosθ)

= 1