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If cos 2θ = 0, determine [θcosθsinθcosθsinθ0sinθ0cosθ]2 - Mathematics

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प्रश्न

If cos 2θ = 0, determine  `[(theta, costheta, sintheta),(costheta, sintheta, 0),(sintheta, 0, costheta)]^2`

योग
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उत्तर

Given cos 2θ = 0

Let A = `[(theta, costheta, sintheta),(costheta, sintheta, 0),(sintheta, 0, costheta)]^2`

A = `[|(sintheta, 0),(0, costheta)| - cos|(costheta, 0),(sintheta, costheta)| + sintheta|(costheta, sintheta),(sintheta, 0)|]^2`

A = `[0 - cos theta(costheta - 0) + sintheta(0 - sin^2theta)]^2`

A = `[- cos3theta - sintheta]2`

A = `[cos^3theta + sin^3theta]^2`  .......(1)

cos 2θ = 0

⇒ 2θ = `pi/2`

⇒ θ = `pi/4`

Substituting θ = `pi/4` in equation (1) we get

A = `[cos^3pi/4 + sin^3 pi/4]^2`

= `[(1/sqrt(2))^3 + (1/sqrt(2))^3]^2`

= `[2 xx (1/sqrt(2))^3]^2`

= `[2 xx 1/(2sqrt(2))]^2`

=`[1/sqrt(2)]^2`

A = `1/2`

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Determinants
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 7: Matrices and Determinants - Exercise 7.4 [पृष्ठ ४०]

APPEARS IN

सामाचीर कलवी Mathematics - Volume 1 and 2 [English] Class 11 TN Board
अध्याय 7 Matrices and Determinants
Exercise 7.4 | Q 5 | पृष्ठ ४०

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