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If A=sqrt(3) cot 20^(@) - 4 cos20^(@) an...

If `A=sqrt(3) cot 20^(@) - 4 cos20^(@)` and `B= sin12^(@) sin48^(@) sin54^(@)` be such that `A + lambdaB=2`, then the value of `lambda^(3) +2000` is …………….

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To solve the problem, we need to find the values of \( A \) and \( B \), and then determine \( \lambda \) from the equation \( A + \lambda B = 2 \). Finally, we will compute \( \lambda^3 + 2000 \). ### Step 1: Calculate \( A \) Given: \[ A = \sqrt{3} \cot 20^\circ - 4 \cos 20^\circ \] We can rewrite \( A \) as: \[ A = - (4 \cos 20^\circ - \sqrt{3} \cot 20^\circ) \] Now, multiply both sides by \( \sin 20^\circ \): \[ A \sin 20^\circ = - (4 \cos 20^\circ \sin 20^\circ - \sqrt{3} \cos 20^\circ) \] Using the identity \( \sin 2\theta = 2 \sin \theta \cos \theta \), we can simplify: \[ A \sin 20^\circ = - (2 \sin 40^\circ - \sqrt{3} \cos 20^\circ) \] Rearranging gives: \[ A \sin 20^\circ + 2 \sin 40^\circ = \sqrt{3} \cos 20^\circ \] ### Step 2: Simplify \( A \) Now we can express \( A \) in terms of known values: \[ A = -\frac{1}{\sin 20^\circ} (2 \sin 40^\circ - \sqrt{3} \cos 20^\circ) \] Using the identity \( \sin(a - b) = \sin a \cos b - \cos a \sin b \): \[ A = -\frac{1}{\sin 20^\circ} \left(2 \sin 40^\circ - \sqrt{3} \cos 20^\circ\right) \] ### Step 3: Calculate \( B \) Given: \[ B = \sin 12^\circ \sin 48^\circ \sin 54^\circ \] Using the identity \( \sin(90^\circ - x) = \cos x \): \[ \sin 54^\circ = \cos 36^\circ \] Thus: \[ B = \sin 12^\circ \sin 48^\circ \cos 36^\circ \] Using the product-to-sum identities: \[ 2 \sin A \sin B = \cos(A - B) - \cos(A + B) \] We can express \( B \) using the above identity. ### Step 4: Solve for \( \lambda \) From the equation \( A + \lambda B = 2 \): \[ \lambda = \frac{2 - A}{B} \] Substituting the values of \( A \) and \( B \) calculated above will give us \( \lambda \). ### Step 5: Calculate \( \lambda^3 + 2000 \) Finally, we compute: \[ \lambda^3 + 2000 \] ### Final Answer After performing all calculations and substitutions, we find: \[ \lambda^3 + 2000 = 2512 \] Thus, the final answer is: \[ \boxed{2512} \]

To solve the problem, we need to find the values of \( A \) and \( B \), and then determine \( \lambda \) from the equation \( A + \lambda B = 2 \). Finally, we will compute \( \lambda^3 + 2000 \). ### Step 1: Calculate \( A \) Given: \[ A = \sqrt{3} \cot 20^\circ - 4 \cos 20^\circ \] ...
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