Lösning 1.8.1a
Förberedande kurs i matematik
(Skillnad mellan versioner)
(Ny sida: <math>\displaystyle (3-2i)(4+i-(6-2i)) = (3-2i)(-2+3i)=</math> <math>\displaystyle =(3\cdot (-2) + 3 \cdot 3i -2i\cdot(-2) -2i\cdot 3i = -6 +9i + 4i +6=</math> <math>/displaystyle =13i) |
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(2 mellanliggande versioner visas inte.) | |||
Rad 1: | Rad 1: | ||
- | <math>\ | + | <math>\begin{align}(1+2i)\left(2-\frac{i}{4}\right)&=1\cdot2-1\cdot\frac{i}{4}+2i\cdot2-2i\cdot\frac{i}{4}=\\&= 2-\frac{i}{4}+4i+\frac{1}{2}=\\&=\frac{5}{2}+\frac{15i}{4}\end{align}</math> |
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Nuvarande version
\displaystyle \begin{align}(1+2i)\left(2-\frac{i}{4}\right)&=1\cdot2-1\cdot\frac{i}{4}+2i\cdot2-2i\cdot\frac{i}{4}=\\&= 2-\frac{i}{4}+4i+\frac{1}{2}=\\&=\frac{5}{2}+\frac{15i}{4}\end{align}