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Evaluate cos 40 ^(@) cosec 50 ^(@)+ ...

Evaluate
` cos 40 ^(@) cosec 50 ^(@)+ sin 50 ^(@) sec 40 ^(@) `

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To evaluate the expression \( \cos 40^\circ \csc 50^\circ + \sin 50^\circ \sec 40^\circ \), we will follow these steps: ### Step 1: Rewrite \(\csc 50^\circ\) and \(\sec 40^\circ\) We know that: \[ \csc 50^\circ = \frac{1}{\sin 50^\circ} \] and \[ \sec 40^\circ = \frac{1}{\cos 40^\circ} \] ### Step 2: Substitute the identities into the expression Substituting these identities into the original expression gives us: \[ \cos 40^\circ \cdot \frac{1}{\sin 50^\circ} + \sin 50^\circ \cdot \frac{1}{\cos 40^\circ} \] This simplifies to: \[ \frac{\cos 40^\circ}{\sin 50^\circ} + \frac{\sin 50^\circ}{\cos 40^\circ} \] ### Step 3: Use the identity \(\sin 50^\circ = \cos(90^\circ - 50^\circ) = \cos 40^\circ\) Since \(\sin 50^\circ = \cos 40^\circ\), we can rewrite the expression: \[ \frac{\cos 40^\circ}{\cos 40^\circ} + \frac{\cos 40^\circ}{\cos 40^\circ} \] This simplifies to: \[ 1 + 1 \] ### Step 4: Final Calculation Adding these values together gives: \[ 1 + 1 = 2 \] ### Conclusion Thus, the value of the expression \( \cos 40^\circ \csc 50^\circ + \sin 50^\circ \sec 40^\circ \) is: \[ \boxed{2} \]
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ICSE-CHAPTER REVISION (STAGE 2) -TRIGONOMETRY
  1. Evaluate : (cos 58 ^(@))/(sin 32^(@)) +(sin 22^(@))/(cos 68^(@)) - ...

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  2. Evaluate without using trigonometric tables. 2(("tan" 35^(@))/("cot"...

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  3. Evaluate : sec 26^(@) sin 64^(@) + (cosec 33^(@))/(sec 57^(@))

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  4. Evaluate ( 5 sin 66 ^(@))/( cos 24 ^(@)) -( 2 cot 85^(@))/(tan 5^(@...

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  5. Evaluate cos 40 ^(@) cosec 50 ^(@)+ sin 50 ^(@) sec 40 ^(@)

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  6. Evaluate sin 27 ^(@) sin 63 ^(@) - cos 63^(@) cos 27 ^(@)

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  7. Evaluate : 3(sin 72^(@))/(cos 18^(@))-(sec 32^(@))/(cosec 58^(@))

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  8. Evaluate 3 cos 80 ^(@) cosec 10 ^(@) + 2 cos 59 ^(@) cosec 31 ^(@...

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  9. Evaluate : (cos 75^(@))/ (sin 15^(@)) + (sin 12^(@))/ (cos 78^(@)) -...

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  10. Prove that : sec ^(2) (90 ^(@) - theta) - (1)/(cot ^(2) ( 90 ^(...

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  11. Find theta; if sin(theta + 36^@) = cos theta; where theta + 36^@ is a...

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  12. If in Delta ABC , angle C = 90 ^(@) prove that: ( 1+ tan A)/(1- ...

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  13. If cot A = (12)/(5) , verify tan ^(2) A - sin ^(2) A = sin ^(4) ...

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  14. In a right triangle ABC, right angled at B . The ratio of AB to AC = ...

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  15. If cot theta = (3)/(4) find the value of : ( sin theta- cos theta...

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  16. If cosec A = sqrt3 , find the value of: (2 sin ^(2)A + 3 cot ^(2)...

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  17. In an acute angled triangle A B C , if tan(A+B-C)=1 and ,sec(B+C-A)=2,...

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  18. Prove that sin 30 ^(@) = (1)/(2).

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  19. If tan (A-B) = (1)/(sqrt3) and sin A = (1)/(sqrt2) find the value o...

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  20. In the following figures AB = 4 m and ED = 3m. If sin alpha = (3)...

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