w = logspace(-3, 4, 100)

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mag = sqrt((10 + 5 * w.^2).^2 + (49 * w).^2) ./ (100 + w.^2)

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db = 20 * log10(mag)

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phase = atand(49 * w ./ (10 + 5 * w.^2))

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semilogx(w, db)

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semilogx(w, phase)

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H = tf([5 1], [1 10])

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bode(H)