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Evaluate : (cos 58 ^(@))/(sin 32^(@))...

Evaluate :
` (cos 58 ^(@))/(sin 32^(@)) +(sin 22^(@))/(cos 68^(@)) - cos 90 ^(@) `

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The correct Answer is:
To evaluate the expression \( \frac{\cos 58^\circ}{\sin 32^\circ} + \frac{\sin 22^\circ}{\cos 68^\circ} - \cos 90^\circ \), we will follow these steps: ### Step 1: Rewrite the sine and cosine functions We can use the co-function identities: - \( \sin(90^\circ - \theta) = \cos(\theta) \) - \( \cos(90^\circ - \theta) = \sin(\theta) \) Using these identities, we rewrite \( \sin 32^\circ \) and \( \cos 68^\circ \): - \( \sin 32^\circ = \sin(90^\circ - 58^\circ) = \cos 58^\circ \) - \( \cos 68^\circ = \cos(90^\circ - 22^\circ) = \sin 22^\circ \) ### Step 2: Substitute the rewritten values Now we substitute these identities back into the expression: \[ \frac{\cos 58^\circ}{\sin 32^\circ} = \frac{\cos 58^\circ}{\cos 58^\circ} = 1 \] \[ \frac{\sin 22^\circ}{\cos 68^\circ} = \frac{\sin 22^\circ}{\sin 22^\circ} = 1 \] ### Step 3: Substitute into the original expression Now we can substitute these values back into the original expression: \[ 1 + 1 - \cos 90^\circ \] ### Step 4: Evaluate \( \cos 90^\circ \) We know that: \[ \cos 90^\circ = 0 \] ### Step 5: Final calculation Now we can complete the calculation: \[ 1 + 1 - 0 = 2 \] ### Final Answer The value of the expression is \( 2 \). ---
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ICSE-CHAPTER REVISION (STAGE 2) -TRIGONOMETRY
  1. The length of a string between a kite and a point on the ground is 90 ...

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  2. In the following figure , angle B = 90 ^(@) angle ADB = 30 ^(@) and a...

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  3. Evaluate : (cos 58 ^(@))/(sin 32^(@)) +(sin 22^(@))/(cos 68^(@)) - ...

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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