What is the variance of the data set {3, 5, 7, 9, 11, 13}?
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Math question: What is the 5th derivative of f(x) = cos(3x) + ln(x)?
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Math question: In triangle XYZ, angle X measures 60 degrees and angle Y measures 90 degrees. If the angle bisector of angle XYZ intersects side XZ at point P, find the measure of angle XPY.