88/1000, 1-1/2+1/3-1/4+...=? (alternating harmonic series)

86/1000, the small-angle approximation, sinθ≈θ

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87/1000, how to linearize a multi-variable function, calculus 3

84/1000, infinity minus infinity, calculus 1 limit

80/1000, 1+1/2+1/3+1/4+...., the harmonic series diverges, calculus 2

85/1000, why is the integral of 1/x = ln(x)+C?

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