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The Fourier transform F(k) of a function f(x) is defined as $$F\left( k \right)\int_{ - \infty }^\infty {dxf\left( x \right)\exp \left( {ikx} \right).} $$     Then F(k) for f(x) = exp(-x2) is $$\left[ {{\text{Given: }}\int_{ - \infty }^\infty {\exp \left( { - {x^2}} \right)dx = \sqrt \pi } } \right]$$

A. $$\pi \exp \left( { - k} \right)$$

B. $$\sqrt \pi \exp \left( {\frac{{ - {k^2}}}{4}} \right)$$

C. $$\frac{{\sqrt \pi }}{2}\exp \left( {\frac{{ - {k^2}}}{2}} \right)$$

D. $$\sqrt {2\pi } \exp \left( { - {k^2}} \right)$$

Answer: Option B


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