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Let $$\vec{a}$$ and $$\vec{b}$$ be the vectors along the diagonal of a parallelogram having area $$2\sqrt{2}$$. Let the angle between $$\vec{a}$$ and $$\vec{b}$$ be acute. $$|\vec{a}| = 1$$ and $$|\vec{a} \cdot \vec{b}| = |\vec{a} \times \vec{b}|$$. If $$\vec{c} = 2\sqrt{2}(\vec{a} \times \vec{b}) - 2\vec{b}$$, then an angle between $$\vec{b}$$ and $$\vec{c}$$ is
Let the diagonals of the parallelogram be
$$\vec a \quad \text{and} \quad \vec b$$
Area of a parallelogram in terms of diagonals is
$$\text{Area}=\frac12|\vec a\times \vec b|$$
Given,
$$\frac12|\vec a\times \vec b|=2\sqrt2$$
Hence,
$$|\vec a\times \vec b|=4\sqrt2$$
Now,
$$|\vec a|=1$$
and
$$|\vec a\cdot \vec b|=|\vec a\times \vec b|$$
Let the angle between $$\vec a$$ and $$\vec b$$ be $$\theta$$.
Then,
$$|\vec a||\vec b|\cos\theta=|\vec a||\vec b|\sin\theta$$
$$\tan\theta=1$$
Since the angle is acute,
$$\theta=\frac{\pi}{4}$$
Also,
$$|\vec a\times \vec b| = |\vec a||\vec b|\sin\frac{\pi}{4} $$
$$4\sqrt2=1\cdot |\vec b|\cdot \frac1{\sqrt2}$$
$$|\vec b|=8$$
Given,
$$\vec c=2\sqrt2(\vec a\times \vec b)-2\vec b$$
Now,
$$\vec b\cdot(\vec a\times \vec b)=0$$
Therefore,
$$\vec b\cdot\vec c = -2|\vec b|^2 = -2(64) = -128 $$
Also,
$$|2\sqrt2(\vec a\times \vec b)|=16$$
and
$$|-2\vec b|=16$$
Since these two vectors are perpendicular,
$$|\vec c| = \sqrt{16^2+16^2} = 16\sqrt2$$
Let the angle between $$\vec b$$ and $$\vec c$$ be $$\alpha$$.
Then,
$$\cos\alpha = \frac{\vec b\cdot\vec c}{|\vec b||\vec c|} = \frac{-128}{8\cdot16\sqrt2} = -\frac1{\sqrt2} $$
Hence,
$$\alpha=\frac{3\pi}{4}$$
Therefore, the correct answer is
$$\boxed{\text{Option D }\frac{3\pi}{4}}$$
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