Lösning 1.8.1a

Förberedande kurs i matematik

(Skillnad mellan versioner)
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Nuvarande version (20 juni 2012 kl. 12.56) (redigera) (ogör)
 
Rad 1: Rad 1:
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<math>\displaystyle (1+2i)\left( 2-\frac{i}{4} \right) = 1\cdot 2 - 1 \cdot \frac{i}{4}+2i\cdot 2- 2i\cdot \frac{i}{4}=</math>
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<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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<math>\displaystyle = 2-\frac{i}{4}+4i+\frac{1}{2} = \frac{5}{2} + \frac{15 i} {4}</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}