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IIT JEE TRIGONOMETRIC FUNCTIONS Let `f_n(theta)=(cos(theta/2)+cos2theta+cos((7theta)/2)+....+cos(...

125 views · Published 22 September 2017 · 3:44 · Indexed 21 September 2026

Channel: Doubtnut · 2017 · Education

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This is the Solution of question from Cengage Publication Math Book Trigonometry Chapter 6 TRIGONOMETRIC FUNCTIONS written By G. Tewani. You can Find Solution of all math questions from CENGAGE BOOK on our app DOUBTNUT for free. Download Doubtnut from - https://doubtnut.app.link/GdvoLo8GxR

Let `f_n(theta)=(cos(theta/2)+cos2theta+cos((7theta)/2)+....+cos(3n-2)(theta/2))/(sin(theta/2)+sin2theta+sin((7theta)/2)+....+sin(3n-2)(theta/2))`
then
(a)`f_3((3pi)/(16))=sqrt(2)-1`
 (b) `f_5(pi/(28))=sqrt(2)+1`

(c)`f_7(pi/(60))=(2+sqrt(3))`
 (d) none of these

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