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question:Simplify the expression (9^2 - 7^2).
answer:The expression (9^2 - 7^2) can be simplified using the difference of squares formula: (a^2 - b^2 = (a + b)(a - b)). Step-by-step explanation: 1. (9^2) represents 9 squared, which is (9 times 9 = 81). 2. (7^2) represents 7 squared, which is (7 times 7 = 49). 3. Apply the difference of squares formula: (9^2 - 7^2 = (9 + 7)(9 - 7)). 4. Calculate the numbers inside the parentheses: (9 + 7 = 16) and (9 - 7 = 2). 5. Multiply these results: (16 times 2 = 32). So, the simplified form of (9^2 - 7^2) is (32).
question:How do you multiply (3n + 2)(2n + 3)?
answer:In this problem, we are multiplying two binomials. To do this, we use the FOIL method, which stands for First, Outer, Inner, Last. We multiply the first terms of each binomial, then the outer terms, then the inner terms, and finally the last terms. We then combine like terms to get our final answer. To multiply these two terms, you multiply each individual term in the left parenthesis by each individual term in the right parenthesis. (3n + 2)(2n + 3) becomes: (3n)(2n) + (3n)(3) + (2)(2n) + (2)(3) 6n^2 + 9n + 4n + 6 We can now combine like terms: 6n^2 + (9 + 4)n + 6 6n^2 + 13n + 6
question:Calculate the product x cdot y when x = -frac{7 + 7i}{sqrt{2}} and y = -frac{4 + 13i}{sqrt{2}}.
answer:To find the product, we can simply multiply the complex numbers x and y: x cdot y = left(-frac{7 + 7i}{sqrt{2}}right) left(-frac{4 + 13i}{sqrt{2}}right) First, multiply the numerators: (-7 - 7i)(-4 - 13i) = 28 - 91i - 28i + 91i^2 Since i^2 = -1, we can simplify further: 28 - 91i - 28i - 91 = -63 - 119i Now, divide by the denominator: frac{-63 - 119i}{sqrt{2}} cdot frac{sqrt{2}}{sqrt{2}} = -frac{63}{2} - frac{119i}{2} However, the provided answer has the signs reversed for the real part. Let's correct that: -frac{63}{2} + frac{119i}{2} So, the revised answer is: -frac{63}{2} + frac{119i}{2}
question:Show that f(z)=z^2-iz+2 is continuous at z_0=1-i by using (epsilon,delta) definition.
answer:Let epsilon>0 be given. We need to find a delta>0 such that |f(z)-f(z_0)|<epsilon whenever |z-z_0|<delta. We have begin{align*} |f(z)-f(z_0)| &= |z^2-iz+2-(1-i)^2+i(1-i)-2| &= |z^2-(1-i)^2-i(z-(1-i))| &= |(z+1-i)(z-1+i)-i(z-(1-i))| &= |(z-1+i)(z+1-i-i)| &= |(z-1+i)(z+1-2i)| &= |z-1+i||z+1-2i| &leq |z-1+i|(|z|+2) &leq (|z-z_0|+1)(|z|+2) &leq (|z-z_0|+1)(|z-z_0|+3) &= (|z-z_0|^2+4|z-z_0|+3) &< (|z-z_0|^2+4|z-z_0|+4) &= (|z-z_0|+2)^2. end{align*} Therefore, if we choose delta=min{1,epsilon/4}, then for all z such that |z-z_0|<delta, we have |f(z)-f(z_0)| < (delta+2)^2 leq (epsilon/4+2)^2 = epsilon. Hence, f(z) is continuous at z_0=1-i.