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CBSE Class 11-science Answered

prove that sine square eighteen degree plus cosine square thirty six degree  is equal to three by four
Asked by hrushikesh.barik | 30 Oct, 2017, 08:27: PM
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begin mathsize 16px style sin squared 18 degree space plus space cos squared 36 degree equals sin squared 18 degree space plus open parentheses 1 space minus space 2 sin squared 18 degree close parentheses squared........ left parenthesis straight i right parenthesis Considering space straight A space equals space 18 degree sin 36 degree space equals space sin open parentheses 90 degree minus 54 degree close parentheses sin 36 degree space equals cos 54 degree sin 2 straight A equals cos 3 straight A Solving space this space we space get space sin squared 18 degree space equals space fraction numerator 3 space minus space square root of 5 over denominator 8 end fraction Put space this space value space in space equation space left parenthesis straight i right parenthesis and space solving space it space further space we space get space sin squared 18 degree space plus space cos squared 36 degree space equals space 3 over 4 end style
Answered by Sneha shidid | 13 Dec, 2017, 04:48: PM

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CBSE 11-science - Maths
Prove that 2sin^2 y + 4cos(x + y) sinxsiny ny + cos 2 * (x + y) = cos 2x
Asked by apnp31 | 21 Sep, 2020, 12:19: PM
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CBSE 11-science - Maths
Cos5π/4-sin5π/4+tan11π/4-cot11π/4? SIn4530°? Cos (-9π/4)? Sin 120°cos 150°-cos240°sin330°? If tan35°=k then,Tan145°-Tan125°/1+Tan145°.Tan125°?
Asked by Pallapothu.a | 05 Aug, 2020, 04:13: PM
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CBSE 11-science - Maths
clear my doubt
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Asked by kandukuriPraneeth16 | 25 Jul, 2020, 06:18: PM
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CBSE 11-science - Maths
trigonometry ka question hai please solve
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Asked by jaiswalpiyush040 | 20 Jul, 2020, 08:22: AM
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CBSE 11-science - Maths
Prove that cos^2 pi/8 + cos^2 3pi/8 + cos^2 5pi/8 + cos^2 7pi/8 =2  
Asked by anushkapanwar74 | 15 Aug, 2019, 01:26: PM
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CBSE 11-science - Maths
2 tan B + cot B = tan A , show that 2 tan(A-B) = cot B
Asked by agarwalharsh8476 | 06 Aug, 2019, 08:32: PM
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CBSE 11-science - Maths
sinx1sinx2-cosx1cosx2+1=0 the value of tanx1/2*tanx2/2 is alwya equal to?  
Asked by aahnik.mohanty | 29 May, 2019, 08:00: PM
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CBSE 11-science - Maths
For any real x find the minimum and maximum value for the expression 3sin^2x +3sinxcosx + 7cos^2x.
Asked by acv27joy | 10 Dec, 2018, 01:10: PM
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CBSE 11-science - Maths
If sin x + cos x = sqrt{y+(1/y)} such that x belongs to [0,6Π] and y>0 prove that x = Π/4 or 9Π/4.
Asked by acv27joy | 08 Oct, 2018, 09:42: AM
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CBSE 11-science - Maths
(sinø-cosø)^2=1-sin2ø
Asked by abhaysharma2710 | 15 Jul, 2018, 10:09: AM
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