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Arturiano [62]
2 years ago
12

If a = 1/x+1/y , what is the value of 1/a

Mathematics
2 answers:
kykrilka [37]2 years ago
8 0

We are given that <em>a =(1/x) + (1/y)</em> , and need to find the value of (1/a) , as <em>a</em> is the sum of <em>two fractions</em> so we can't reciprocal both sides <em>directly</em> without <em>finding their sum</em> and converting them into a <em>single fraction</em> . So , let's start by simplifying <em>a</em> first

{:\implies \quad \sf a=\dfrac{1}{x}+\dfrac{1}{y}}

{:\implies \quad \sf a=\dfrac{x+y}{xy}}

Now , we knows an indentity ;

  • {\boxed{\bf{{\left(\dfrac{a}{b}\right)}^{-1}=\dfrac{b}{a}}}}

Now , raising to the <em>power -1</em> on both sides :

{:\implies \quad \sf {\left(\dfrac{a}{1}\right)}^{-1}={\left(\dfrac{x+y}{xy}\right)}^{-1}}

{:\implies \quad \bf \therefore \quad \underline{\underline{\dfrac{1}{a}=\dfrac{xy}{x+y}}}}

lana66690 [7]2 years ago
3 0
<h3>Solution</h3>

a=\frac{1}{x}+\frac{1}{y}

so the value of 1/a is…

\begin{aligned}\frac{1}{a}&=\frac{1}{\frac{1}{x}+\frac{1}{y}}\\&\Rightarrow\frac{1}{\frac{y+x}{xy}}\\&\Rightarrow1\times\frac{xy}{y+x}\\&\Rightarrow\frac{xy}{x+y}\end{aligned}

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The probability that the result that is gotten will be a multiple of 3 and 2 will be 2/15.

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From the information, the spinner has 15 equal areas, numbered 1 through 15.

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The best answer is
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