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Evaluate : (5 sin ^(2) 30^(@) + cos ^(2)...

Evaluate : `(5 sin ^(2) 30^(@) + cos ^(2) 45^(@) + 4 tan ^(2) 60^(@))/( 2 sin 30^(@) cos 60^(@) + tan 45^(@))`

A

1

B

`9 (1)/(6)`

C

` 7 (3)/(7)`

D

`(47)/(12)`

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The correct Answer is:
To evaluate the expression \[ \frac{5 \sin^2 30^\circ + \cos^2 45^\circ + 4 \tan^2 60^\circ}{2 \sin 30^\circ \cos 60^\circ + \tan 45^\circ} \] we will follow these steps: ### Step 1: Calculate the trigonometric values - \(\sin 30^\circ = \frac{1}{2}\) - \(\cos 45^\circ = \frac{1}{\sqrt{2}}\) - \(\tan 60^\circ = \sqrt{3}\) - \(\tan 45^\circ = 1\) - \(\cos 60^\circ = \frac{1}{2}\) ### Step 2: Substitute the values into the expression Substituting these values into the expression gives: \[ \frac{5 \left(\frac{1}{2}\right)^2 + \left(\frac{1}{\sqrt{2}}\right)^2 + 4 \left(\sqrt{3}\right)^2}{2 \left(\frac{1}{2}\right) \left(\frac{1}{2}\right) + 1} \] ### Step 3: Simplify the numerator Calculating each term in the numerator: - \(5 \left(\frac{1}{2}\right)^2 = 5 \cdot \frac{1}{4} = \frac{5}{4}\) - \(\left(\frac{1}{\sqrt{2}}\right)^2 = \frac{1}{2}\) - \(4 \left(\sqrt{3}\right)^2 = 4 \cdot 3 = 12\) Now, adding these values together: \[ \frac{5}{4} + \frac{1}{2} + 12 \] To add these fractions, we need a common denominator. The least common multiple of 4 and 2 is 4. Thus, we rewrite \(\frac{1}{2}\) as \(\frac{2}{4}\): \[ \frac{5}{4} + \frac{2}{4} + 12 = \frac{5 + 2}{4} + 12 = \frac{7}{4} + 12 \] To add \(12\) (which is \(\frac{48}{4}\)): \[ \frac{7}{4} + \frac{48}{4} = \frac{55}{4} \] ### Step 4: Simplify the denominator Now, simplifying the denominator: \[ 2 \left(\frac{1}{2}\right) \left(\frac{1}{2}\right) + 1 = 2 \cdot \frac{1}{4} + 1 = \frac{1}{2} + 1 = \frac{1}{2} + \frac{2}{2} = \frac{3}{2} \] ### Step 5: Combine the results Now, we combine the results from the numerator and denominator: \[ \frac{\frac{55}{4}}{\frac{3}{2}} = \frac{55}{4} \cdot \frac{2}{3} = \frac{55 \cdot 2}{4 \cdot 3} = \frac{110}{12} = \frac{55}{6} \] ### Step 6: Convert to mixed fraction Now, we convert \(\frac{55}{6}\) into a mixed fraction: Dividing \(55\) by \(6\): - \(6\) goes into \(55\) \(9\) times (since \(6 \times 9 = 54\)), leaving a remainder of \(1\). Thus, we can write: \[ \frac{55}{6} = 9 \frac{1}{6} \] ### Final Answer: The final answer is \[ 9 \frac{1}{6} \]
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