Bepaal modulus en argument

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Bepaal modulus en argument

1. \(-2-8i\)
2. \(7+3i\)
3. \(-7-8i\)
4. \(5+7i\)
5. \(-3-7i\)
6. \(8-2i\)
7. \(4-7i\)
8. \(7-5i\)
9. \(-5-6i\)
10. \(1+9i\)
11. \(-5i\)
12. \(6+6i\)

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Bepaal modulus en argument

Verbetersleutel

1. \(-2-8i\\ r = \sqrt{(-2)^2+(-8)^2} = \sqrt{68} \\ \alpha = tan^{-1}(\frac{-8}{-2}) \Leftrightarrow \alpha =75^\circ 57' 49{,}5"\text{ of } \alpha = 255^\circ 57' 49{,}5"\\-2-8i\text{ ligt in kwadrant }3, \alpha \text{ ligt dus tussen }180^\circ \text{ en }270^\circ\\ \alpha = 255^\circ 57' 49{,}5"\)
2. \(7+3i\\ r = \sqrt{7^2+3^2} = \sqrt{58} \\ \alpha = tan^{-1}(\frac{3}{7}) \Leftrightarrow \alpha =23^\circ 11' 54{,}9"\text{ of } \alpha = 203^\circ 11' 54{,}9"\\7+3i\text{ ligt in kwadrant }1, \alpha \text{ ligt dus tussen }0^\circ \text{ en }90^\circ\\ \alpha = 23^\circ 11' 54{,}9"\)
3. \(-7-8i\\ r = \sqrt{(-7)^2+(-8)^2} = \sqrt{113} \\ \alpha = tan^{-1}(\frac{-8}{-7}) \Leftrightarrow \alpha =48^\circ 48' 50{,}7"\text{ of } \alpha = 228^\circ 48' 50{,}7"\\-7-8i\text{ ligt in kwadrant }3, \alpha \text{ ligt dus tussen }180^\circ \text{ en }270^\circ\\ \alpha = 228^\circ 48' 50{,}7"\)
4. \(5+7i\\ r = \sqrt{5^2+7^2} = \sqrt{74} \\ \alpha = tan^{-1}(\frac{7}{5}) \Leftrightarrow \alpha =54^\circ 27' 44{,}4"\text{ of } \alpha = 234^\circ 27' 44{,}4"\\5+7i\text{ ligt in kwadrant }1, \alpha \text{ ligt dus tussen }0^\circ \text{ en }90^\circ\\ \alpha = 54^\circ 27' 44{,}4"\)
5. \(-3-7i\\ r = \sqrt{(-3)^2+(-7)^2} = \sqrt{58} \\ \alpha = tan^{-1}(\frac{-7}{-3}) \Leftrightarrow \alpha =66^\circ 48' 5{,}1"\text{ of } \alpha = 246^\circ 48' 5{,}1"\\-3-7i\text{ ligt in kwadrant }3, \alpha \text{ ligt dus tussen }180^\circ \text{ en }270^\circ\\ \alpha = 246^\circ 48' 5{,}1"\)
6. \(8-2i\\ r = \sqrt{8^2+(-2)^2} = \sqrt{68} \\ \alpha = tan^{-1}(\frac{-2}{8}) \Leftrightarrow \alpha =165^\circ 57' 49{,}5"\text{ of } \alpha = 345^\circ 57' 49{,}5"\\8-2i\text{ ligt in kwadrant }4, \alpha \text{ ligt dus tussen }270^\circ \text{ en }360^\circ\\ \alpha = 345^\circ 57' 49{,}5"\)
7. \(4-7i\\ r = \sqrt{4^2+(-7)^2} = \sqrt{65} \\ \alpha = tan^{-1}(\frac{-7}{4}) \Leftrightarrow \alpha =119^\circ 44' 41{,}6"\text{ of } \alpha = 299^\circ 44' 41{,}6"\\4-7i\text{ ligt in kwadrant }4, \alpha \text{ ligt dus tussen }270^\circ \text{ en }360^\circ\\ \alpha = 299^\circ 44' 41{,}6"\)
8. \(7-5i\\ r = \sqrt{7^2+(-5)^2} = \sqrt{74} \\ \alpha = tan^{-1}(\frac{-5}{7}) \Leftrightarrow \alpha =144^\circ 27' 44{,}4"\text{ of } \alpha = 324^\circ 27' 44{,}4"\\7-5i\text{ ligt in kwadrant }4, \alpha \text{ ligt dus tussen }270^\circ \text{ en }360^\circ\\ \alpha = 324^\circ 27' 44{,}4"\)
9. \(-5-6i\\ r = \sqrt{(-5)^2+(-6)^2} = \sqrt{61} \\ \alpha = tan^{-1}(\frac{-6}{-5}) \Leftrightarrow \alpha =50^\circ 11' 39{,}9"\text{ of } \alpha = 230^\circ 11' 39{,}9"\\-5-6i\text{ ligt in kwadrant }3, \alpha \text{ ligt dus tussen }180^\circ \text{ en }270^\circ\\ \alpha = 230^\circ 11' 39{,}9"\)
10. \(1+9i\\ r = \sqrt{1^2+9^2} = \sqrt{82} \\ \alpha = tan^{-1}(\frac{9}{1}) \Leftrightarrow \alpha =83^\circ 39' 35{,}3"\text{ of } \alpha = 263^\circ 39' 35{,}3"\\1+9i\text{ ligt in kwadrant }1, \alpha \text{ ligt dus tussen }0^\circ \text{ en }90^\circ\\ \alpha = 83^\circ 39' 35{,}3"\)
11. \(-5i\\ \text{ Dit complex getal ligt op het negatief gedeelte van de y-as. We hebben geen berekeningen nodig om r of } \alpha \text{ te berekenen.} \\\text{r = }5\\\alpha = 270 ^\circ \\\)
12. \(6+6i\\ r = \sqrt{6^2+6^2} = \sqrt{72} \\ \alpha = tan^{-1}(\frac{6}{6}) \Leftrightarrow \alpha =45^\circ \text{ of } \alpha = 225^\circ \\6+6i\text{ ligt in kwadrant }1, \alpha \text{ ligt dus tussen }0^\circ \text{ en }90^\circ\\ \alpha = 45^\circ \)