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Grade 11Trigonometry

how do you express cos(7x) in terms of cos(x)?

Profile image of tejas ramkumar
15 Years agoGrade 11
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3 Answers

Profile image of Godfrey Classic Prince
15 Years ago

Dear tejas ramkumar,

cos(7x) = 64 cos7(x) - 112 cos5(x) + 56 cos3(x) - 7 cos(x)

Thank You !!

Please approve my answer if you liked it by clicking on "Yes" below..!!!Smile

Profile image of Viral A. Parmar
15 Years ago

convert cos(7x) in cos (3x+4x)

then expand it and after that use cos(3x) formulae and again write cos(4x) as cos(2x+2x) and expand it then use cos(2x) formulae and you will get answer....

thanx

Profile image of Viral A. Parmar
15 Years ago

atleast aprove my answer yaar

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