Common mistakes with special products

Warning — Common mistakes with special products

$(ab+3)^2 \neq a^2b^2+9 \qquad \text{⚠ manca il doppio prodotto } 6ab!$ The square of a sum is not the sum of the squares: $(ab+3)^2 = a^2b^2 + 6ab + 9$ The square of a product, on the other hand, is: $(ab\cdot 3)^2 = 9a^2b^2$. ✓

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Topics: Algebraic calculus
Concepts: Special products · Square of a binomial