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The value of (1)/(2) sin ^(2) 90^(@) sin...

The value of `(1)/(2) sin ^(2) 90^(@) sin^(2) 30^(@) cos ^(2) 45^(@) + 4 tan ^(2) 30^(@) + (1)/(2) sin^(2) 90^(@) - 2 cos ^(2) 90^(@) ` is :

A

`(45)/(24)`

B

`(46)/(24)`

C

`(47)/(24)`

D

`(49)/(24)`

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The correct Answer is:
To solve the expression \[ \frac{1}{2} \sin^2 90^\circ \sin^2 30^\circ \cos^2 45^\circ + 4 \tan^2 30^\circ + \frac{1}{2} \sin^2 90^\circ - 2 \cos^2 90^\circ, \] we will evaluate each trigonometric function step by step. ### Step 1: Calculate \(\sin^2 90^\circ\) \[ \sin 90^\circ = 1 \implies \sin^2 90^\circ = 1^2 = 1. \] ### Step 2: Calculate \(\sin^2 30^\circ\) \[ \sin 30^\circ = \frac{1}{2} \implies \sin^2 30^\circ = \left(\frac{1}{2}\right)^2 = \frac{1}{4}. \] ### Step 3: Calculate \(\cos^2 45^\circ\) \[ \cos 45^\circ = \frac{1}{\sqrt{2}} \implies \cos^2 45^\circ = \left(\frac{1}{\sqrt{2}}\right)^2 = \frac{1}{2}. \] ### Step 4: Calculate \(\tan^2 30^\circ\) \[ \tan 30^\circ = \frac{1}{\sqrt{3}} \implies \tan^2 30^\circ = \left(\frac{1}{\sqrt{3}}\right)^2 = \frac{1}{3}. \] ### Step 5: Calculate \(\cos^2 90^\circ\) \[ \cos 90^\circ = 0 \implies \cos^2 90^\circ = 0^2 = 0. \] ### Step 6: Substitute values into the expression Now we substitute the calculated values back into the expression: \[ \frac{1}{2} \cdot 1 \cdot \frac{1}{4} \cdot \frac{1}{2} + 4 \cdot \frac{1}{3} + \frac{1}{2} \cdot 1 - 2 \cdot 0. \] ### Step 7: Simplify the expression 1. First term: \[ \frac{1}{2} \cdot 1 \cdot \frac{1}{4} \cdot \frac{1}{2} = \frac{1}{16}. \] 2. Second term: \[ 4 \cdot \frac{1}{3} = \frac{4}{3}. \] 3. Third term: \[ \frac{1}{2} \cdot 1 = \frac{1}{2}. \] 4. Fourth term: \[ -2 \cdot 0 = 0. \] Combining all these: \[ \frac{1}{16} + \frac{4}{3} + \frac{1}{2}. \] ### Step 8: Find a common denominator The least common multiple (LCM) of 16, 3, and 2 is 48. We convert each term: 1. \(\frac{1}{16} = \frac{3}{48}\), 2. \(\frac{4}{3} = \frac{64}{48}\), 3. \(\frac{1}{2} = \frac{24}{48}\). ### Step 9: Combine the fractions Now, we add these fractions: \[ \frac{3}{48} + \frac{64}{48} + \frac{24}{48} = \frac{3 + 64 + 24}{48} = \frac{91}{48}. \] ### Final Answer Thus, the value of the expression is: \[ \frac{91}{48}. \] ---
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S CHAND IIT JEE FOUNDATION-TRIGONOMETRICAL RATIOS OF STANDARD ANGLES -Question Bank - 33
  1. The value of a sin 0^(@) + b cos 90^(@)+ c tan 45^(@) is

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  2. The value of (sin 30^(@) - cos 60^(@) + tan 45^(@))/(cos 90^(@) + tan ...

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  3. The value of (1)/(2) sin ^(2) 90^(@) sin^(2) 30^(@) cos ^(2) 45^(@) + ...

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  4. The value of (cos 0^(@) + sin 45^(@) + sin 30^(@)) (sin 90^(@) - cos 4...

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  5. (tan 60^(@) - tan 30^(@))/(1 + tan 60^(@) tan 30^(@)) equal

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  6. Find the value of x, if sin 2 x = sin 60^(@) cos 30^(@) - cos 60^(@...

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  7. tan 26^(@) - cot 64^(@) equals

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  8. (sin19^@)/(cos71^@)+(cos73^@)/(sin17^@)

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  9. Consider the following equations : 1 . (cos 75^(@))/( sin 15 ^(@)) +...

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  10. sin ^(2) 25^(@) + sin ^(2) 65^(@) is equal to

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  11. If sin (30 ^(@) - theta) = cos (60 ^(@) + phi) , then

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  12. The value of cot 15^(@) cot 16^(@) cot 17^(@) . . . . . cot 73^(@) cot...

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  13. If sin theta = cos theta, then value of theta is :

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  14. Value of cos^(2) 5^(@) + cos^(2) 10^(@) + cos^(2) 80^(@) + cos ^(2) 85...

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  15. If sin 3 theta = cos (theta - 2^(@)) where 3 theta and (theta - 2^(@...

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  16. If tan theta = 1 and sin phi = (1)/( sqrt(2)) , then the value of co...

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  17. If x cos 60^(@) + y cos 0^(@) = 3 and 4x sin 30^(@) - y cot 45^(@) =...

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  18. Which one of the following is true ?

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  19. If x + y = 90^(@) , then what is sqrt( cos x cosec y - cos x sin...

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  20. If 0^(@) lt theta lt 90^(@) and cos^(2) theta - sin^(2) theta = (1)/(...

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