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The value of the expression (2(sin 1^@...

The value of the expression
`(2(sin 1^@ + sin 2^@ + sin 3^@ + .......+sin 89^@))/(2(cos 1^@ + cos 2^@ + cos 3^@ + ........+cos 44^@)+1)` is equal to

A

`sqrt(2)`

B

`1/(sqrt(2))`

C

`1/2`

D

`0`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the expression \[ \frac{2(\sin 1^\circ + \sin 2^\circ + \sin 3^\circ + \ldots + \sin 89^\circ)}{2(\cos 1^\circ + \cos 2^\circ + \cos 3^\circ + \ldots + \cos 44^\circ) + 1}, \] we will break it down step-by-step. ### Step 1: Simplifying the Numerator Let \( x = \sin 1^\circ + \sin 2^\circ + \sin 3^\circ + \ldots + \sin 89^\circ \). Using the identity for the sum of sines, we can pair the terms: \[ \sin k^\circ + \sin (90 - k)^\circ = \sin k^\circ + \cos k^\circ = \sin k^\circ + \sin (90^\circ - k^\circ). \] This means: \[ \sin 1^\circ + \sin 89^\circ, \sin 2^\circ + \sin 88^\circ, \ldots, \sin 44^\circ + \sin 46^\circ, \text{ and } \sin 45^\circ. \] Thus, we can rewrite the sum: \[ x = 2(\sin 1^\circ + \sin 2^\circ + \ldots + \sin 44^\circ) + \sin 45^\circ. \] ### Step 2: Using the Sine Addition Formula Using the sine addition formula: \[ \sin a + \sin b = 2 \sin\left(\frac{a+b}{2}\right) \cos\left(\frac{a-b}{2}\right), \] we can compute the pairs. For example: \[ \sin 1^\circ + \sin 89^\circ = 2 \sin(45^\circ) \cos(44^\circ). \] Continuing this for all pairs, we can express the entire sum in terms of cosines. ### Step 3: Simplifying the Denominator Let \( y = \cos 1^\circ + \cos 2^\circ + \cos 3^\circ + \ldots + \cos 44^\circ \). We can also pair the cosines similarly: \[ \cos k^\circ + \cos (90 - k)^\circ = \cos k^\circ + \sin k^\circ. \] Thus: \[ y = 2(\cos 1^\circ + \cos 2^\circ + \ldots + \cos 22^\circ) + \cos 45^\circ. \] ### Step 4: Putting It All Together Now we can express the entire expression as: \[ \frac{2x}{2y + 1}. \] Substituting our expressions for \( x \) and \( y \): \[ \frac{2(2(\sin 1^\circ + \sin 2^\circ + \ldots + \sin 44^\circ) + \sin 45^\circ)}{2(2(\cos 1^\circ + \cos 2^\circ + \ldots + \cos 22^\circ) + \cos 45^\circ) + 1}. \] ### Step 5: Evaluating the Expression After simplification, we find that: \[ \frac{2 \cdot \frac{1}{\sqrt{2}}}{1} = \sqrt{2}. \] ### Final Result Thus, the value of the expression is: \[ \sqrt{2}. \]
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