IntermediateLinear Algebra10 min
Rank in disguise
State the rank of A, then describe its null space and column space.
RankNull spaceRank–nullity theorem
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Quick investigations
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Spot the mistakeFoundationHigh School60s
A student solves x² = 5x and concludes x = 5. What went wrong?
Topic: Quadratic equations
Estimate firstFoundationMiddle School30s
Without a calculator, is √72 closer to 8 or to 9?
Topic: Number sense
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