SOLUTION: sinē(1°)+sinē(2°)+···+sinē(88°)+sinē(89°)

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Question 867653: sinē(1°)+sinē(2°)+···+sinē(88°)+sinē(89°)
Answer by Edwin McCravy(20062)   (Show Source): You can put this solution on YOUR website!
sinē(1°)+sinē(2°)+···+sinē(88°)+sinē(89°) =

Put some terms in the middle:

sinē(1°)+sinē(2°)+···+sinē(44°)+sinē(45°)+sinē(46°)+···+sinē(88°)+sinē(89°)

sinē(1°)+sinē(2°)+···+sinē(44°)+sinē(45°)+sinē(90°-44°)+···+sinē(90°-2°)+sinē(90°-1°)

Use the fact that sin(90°-q) = cos(q) 

sinē(1°)+sinē(2°)+···+sinē(44°)+sinē(45°)+cosē(44°)+···+cosē(2°)+cosē(1°) =

Rearrange the terms putting the 

1st and 89th terms together,

2nd and 88th terms together,

···

44th and 46th terms together: 

[sinē(1°)+cosē(1°)]+[sinē(2°)+cosē(2°)]+···+[sinē(44°)+cosē(44°)]+sinē(45°) =

Use the fact that sinē(q)+cosē(q) = 1

1 + 1 + ··· + 1 + sinē(45°), where there are 44 1's.

44 + sinē(45°) =

44 +  =

44 +  = 

44 +  =

44.5 

Edwin


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