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Evaluate: (sec 29^(@))/("cosec" 61^(@)) ...

Evaluate: `(sec 29^(@))/("cosec" 61^(@)) + 2 cot 8^(@) cot 17^(@) cot 45^(@) cot 73^(@) cot82^(@) - 3(sin^(2) 38^(@) + sin^(2) 52^(@)) + 4[cos theta sin(90^(@) - theta) + sin theta cos (90^(@) - theta)]`

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To evaluate the expression \[ \frac{\sec 29^\circ}{\csc 61^\circ} + 2 \cot 8^\circ \cot 17^\circ \cot 45^\circ \cot 73^\circ \cot 82^\circ - 3(\sin^2 38^\circ + \sin^2 52^\circ) + 4\left[\cos \theta \sin(90^\circ - \theta) + \sin \theta \cos(90^\circ - \theta)\right], \] we will break it down step by step. ### Step 1: Evaluate \(\frac{\sec 29^\circ}{\csc 61^\circ}\) Using the identity \(\csc \theta = \sec(90^\circ - \theta)\): \[ \csc 61^\circ = \sec(90^\circ - 61^\circ) = \sec 29^\circ. \] Thus, \[ \frac{\sec 29^\circ}{\csc 61^\circ} = \frac{\sec 29^\circ}{\sec 29^\circ} = 1. \] ### Step 2: Evaluate \(2 \cot 8^\circ \cot 17^\circ \cot 45^\circ \cot 73^\circ \cot 82^\circ\) Using the identity \(\cot(90^\circ - \theta) = \tan \theta\): \[ \cot 73^\circ = \tan 17^\circ \quad \text{and} \quad \cot 82^\circ = \tan 8^\circ. \] Thus, we can rewrite: \[ \cot 8^\circ \cot 17^\circ \cot 45^\circ \cot 73^\circ \cot 82^\circ = \cot 8^\circ \tan 8^\circ \cot 17^\circ \tan 17^\circ \cdot 1. \] Since \(\cot \theta \tan \theta = 1\): \[ \cot 8^\circ \tan 8^\circ = 1 \quad \text{and} \quad \cot 17^\circ \tan 17^\circ = 1. \] Thus, \[ \cot 8^\circ \cot 17^\circ \cot 45^\circ \cot 73^\circ \cot 82^\circ = 1. \] So, \[ 2 \cot 8^\circ \cot 17^\circ \cot 45^\circ \cot 73^\circ \cot 82^\circ = 2. \] ### Step 3: Evaluate \(-3(\sin^2 38^\circ + \sin^2 52^\circ)\) Using the identity \(\sin^2 \theta + \cos^2 \theta = 1\): \[ \sin^2 52^\circ = \cos^2 38^\circ. \] Thus, \[ \sin^2 38^\circ + \sin^2 52^\circ = \sin^2 38^\circ + \cos^2 38^\circ = 1. \] So, \[ -3(\sin^2 38^\circ + \sin^2 52^\circ) = -3 \cdot 1 = -3. \] ### Step 4: Evaluate \(4\left[\cos \theta \sin(90^\circ - \theta) + \sin \theta \cos(90^\circ - \theta)\right]\) Using the identity \(\sin(90^\circ - \theta) = \cos \theta\): \[ \cos \theta \sin(90^\circ - \theta) + \sin \theta \cos(90^\circ - \theta) = \cos \theta \cos \theta + \sin \theta \sin \theta = \cos^2 \theta + \sin^2 \theta = 1. \] Thus, \[ 4\left[\cos \theta \sin(90^\circ - \theta) + \sin \theta \cos(90^\circ - \theta)\right] = 4 \cdot 1 = 4. \] ### Final Calculation Now, we combine all parts: \[ 1 + 2 - 3 + 4 = 4. \] Thus, the final answer is \[ \boxed{4}. \]
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LUCENT PUBLICATION-ELEMENTARY TRIGONOMETRIC IDENTITIES -EXERCISE 11B
  1. Evaluate: (sec 29^(@))/("cosec" 61^(@)) + 2 cot 8^(@) cot 17^(@) cot 4...

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  2. If sec theta=4x and tan theta=4/x, (x ne 0) then the value of 8(x^2-1/...

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  3. 2-cos^(2)theta =3 sintheta costheta , sintheta ne cos theta, then the...

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  4. If sintheta+costheta=sqrt(2)sin(90^(@)-theta) , then the value of co...

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  5. If x sin^(3) theta + y cos^(3) theta = sin theta cos theta and x sin t...

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  6. A and B are complementary angles, then find the value of sinAcosB+cosA...

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  7. The least value of 2sin^2theta+3cos^2theta is

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  8. sec^(4)theta - sec^(2)theta equals

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  9. If costheta+cos^(2)theta=1, then find the value of sin^(4)theta+sin^(2...

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  10. If sec theta - cosec theta = 0 , then the value of (sec theta + cosec ...

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  11. If P sin theta = sqrt(3) and P costheta =1, then the value of P is:

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  12. If mu(n) = cos^(n)alpha + sin^(n)alpha, then the value of 2mu(6)- 3mu(...

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  13. If sin(x+y)=cos[3(x+y)], then the value of tan[2(x+y)] is.

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  14. The value of (1+sec20^(@)+cot70^(@))(1-"cosec"20^(@)+tan70^(@)) is...

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  15. If alpha is a positive acute angle and 2sin alpha+15cos^(2)alpha=7, th...

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  16. The value of theta [0^(@) lt theta lt 90^(@)], for which (cos theta)/(...

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  17. If sec theta+tan theta=3, then the value of sec theta is: यदि sec th...

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  18. If tan2theta.tan4theta=1 , then the value of tan3theta is

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  19. If costheta+sectheta=sqrt(3) , then the value of (cos^(3)theta+sec...

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  20. If 2ycos theta =x sin theta and 2x sectheta -y "cosec"theta =3, then t...

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  21. If sectheta + tan theta = sqrt(3), then the positive value of sin thet...

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