Math, asked by Anonymous, 1 year ago

prove that

cos20cos40cos60cos80 = 1/16

note: all are degree like 20 degree and 40 degree

Answers

Answered by sayak2k1moyoukh

Answer:

Step-by-step explanation:

Attachments:

sayak2k1moyoukh: Sin 2x= 2 (sin x)(cos x)

sayak2k1moyoukh: It is just a formulah

sayak2k1moyoukh: To get it's proof kindly see your math text book

sayak2k1moyoukh: We know , sin(x+y)=(sin x)(cos y)+(cos x)(sin y). Now substituting y=x on above equations

sayak2k1moyoukh: We get sin(x+x)=(sin x)(cos x)+(cos x)(sin x)

sayak2k1moyoukh: Do you understand?

Anonymous: ya a little but thanks for ur great efforts

sayak2k1moyoukh: Thank you too

sayak2k1moyoukh: Very 1 St line is just a adjustment to use this formulah

sayak2k1moyoukh: Trigonometry's problem is nothing but adjustment

Answered by Anonymous

Answer :- Refer the attachment !

Attachments:

Anonymous: second step kya tha?

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