Math, asked by hareesh4444, 11 months ago

cos20+cos40+cos60+.....cos180​

Answers

Answered by filus139
2

Answer:

answer is 1

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Answered by akaash12372
0

Step-by-step explanation:

APPLY FORMULAE

ANGLES ARE IN AP MUST*

eg 20+40+60..........180

find n

n= 9 20/2=10

sin (nd/2) cos(a+(n-1)/2 d/2)  / sin (d/2)

sin (90) cos (100) / sin 10

sin 90 cos (90+10) / sin 10

-sin 10/sin10

= -1

I HAVE TRIED TO GIVE EASIEST METHOD HOPE IT HELPS U

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