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Bezzdna [24]
3 years ago
7

Write the expression 2i^15-i^7 in the standard form a + bi

Mathematics
1 answer:
elixir [45]3 years ago
7 0
\bf 2i^{15}-i^7\qquad 
\begin{cases}
i^2=\sqrt{-1}\cdot \sqrt{-1}\implies \sqrt{(-1)^2}\implies -1\\\\
i^4=i^2\cdot i^2\implies -1\cdot -1\implies 1
\end{cases}\\\\
-----------------------------\\\\
2i^{4+4+4+2+1}-i^{4+2+1}\implies 2i^4i^4i^4i^2i^1-i^4i^2i^1
\\\\\\
(2\cdot 1\cdot 1\cdot 1\cdot -1\cdot i)-(1\cdot -1\cdot i)\implies -2i-(-i)
\\\\\\
-2i+i\implies -i\implies \boxed{0-i}
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The sigma notation would be:
∑ (from n=1 to ∞) 4800 * (1/4)ⁿ , where n is the year. 
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+
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Year 5: 4800 * (1/4)⁵ = 4.68 = ~ 5
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3 years ago
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An expression that is equivalent to (-8a-1)-(-7a+5)
horrorfan [7]

Answer:

Step-by-step explanation:

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5 0
2 years ago
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