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复数乘法
<div class="ques-view"><p>复数可以写成 <span class="katex"><span class="katex-mathml"><math><mrow><mo>(</mo><mi>A</mi><mo>+</mo><mi>B</mi><mi>i</mi><mo>)</mo></mrow>(A + Bi)</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.75em;"></span><span class="strut bottom" style="height:1em;vertical-align:-0.25em;"></span><span class="base textstyle uncramped"><span class="mopen">(</span><span class="mord mathit">A</span><span class="mbin">+</span><span class="mord mathit" style="margin-right:0.05017em;">B</span><span class="mord mathit">i</span><span class="mclose">)</span></span></span></span> 的常规形式，其中 <span class="katex"><span class="katex-mathml"><math><mrow><mi>A</mi></mrow>A</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit">A</span></span></span></span> 是实部，<span class="katex"><span class="katex-mathml"><math><mrow><mi>B</mi></mrow>B</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.05017em;">B</span></span></span></span> 是虚部，<span class="katex"><span class="katex-mathml"><math><mrow><mi>i</mi></mrow>i</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.65952em;"></span><span class="strut bottom" style="height:0.65952em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit">i</span></span></span></span> 是虚数单位，满足 <span class="katex"><span class="katex-mathml"><math><mrow><msup><mi>i</mi><mn>2</mn></msup><mo>=</mo><mo>−</mo><mn>1</mn></mrow>i^2 = -1</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.8141079999999999em;"></span><span class="strut bottom" style="height:0.897438em;vertical-align:-0.08333em;"></span><span class="base textstyle uncramped"><span class="mord"><span class="mord mathit">i</span><span class="msupsub"><span class="vlist"><span style="top:-0.363em;margin-right:0.05em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span><span class="reset-textstyle scriptstyle uncramped mtight"><span class="mord mathrm mtight">2</span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span>​</span></span></span></span><span class="mrel">=</span><span class="mord">−</span><span class="mord mathrm">1</span></span></span></span>；也可以写成极坐标下的指数形式 <span class="katex"><span class="katex-mathml"><math><mrow><mo>(</mo><mi>R</mi><mo>×</mo><msup><mi>e</mi><mrow><mo>(</mo><mi>P</mi><mi>i</mi><mo>)</mo></mrow></msup><mo>)</mo></mrow>(R\times e^{(Pi)})</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.8879999999999999em;"></span><span class="strut bottom" style="height:1.138em;vertical-align:-0.25em;"></span><span class="base textstyle uncramped"><span class="mopen">(</span><span class="mord mathit" style="margin-right:0.00773em;">R</span><span class="mbin">×</span><span class="mord"><span class="mord mathit">e</span><span class="msupsub"><span class="vlist"><span style="top:-0.363em;margin-right:0.05em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span><span class="reset-textstyle scriptstyle uncramped mtight"><span class="mord scriptstyle uncramped mtight"><span class="mopen mtight">(</span><span class="mord mathit mtight" style="margin-right:0.13889em;">P</span><span class="mord mathit mtight">i</span><span class="mclose mtight">)</span></span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span>​</span></span></span></span><span class="mclose">)</span></span></span></span>，其中 <span class="katex"><span class="katex-mathml"><math><mrow><mi>R</mi></mrow>R</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.00773em;">R</span></span></span></span> 是复数模，<span class="katex"><span class="katex-mathml"><math><mrow><mi>P</mi></mrow>P</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.13889em;">P</span></span></span></span> 是辐角，<span class="katex"><span class="katex-mathml"><math><mrow><mi>i</mi></mrow>i</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.65952em;"></span><span class="strut bottom" style="height:0.65952em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit">i</span></span></span></span> 是虚数单位，其等价于三角形式 <span class="katex"><span class="katex-mathml"><math><mrow><mo>(</mo><mi>R</mi><mo>(</mo><mi>cos</mi><mo>(</mo><mi>P</mi><mo>)</mo><mo>+</mo><mi>i</mi><mi>sin</mi><mo>(</mo><mi>P</mi><mo>)</mo><mo>)</mo></mrow>(R(\cos (P) + i \sin (P))</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.75em;"></span><span class="strut bottom" style="height:1em;vertical-align:-0.25em;"></span><span class="base textstyle uncramped"><span class="mopen">(</span><span class="mord mathit" style="margin-right:0.00773em;">R</span><span class="mopen">(</span><span class="mop">cos</span><span class="mopen">(</span><span class="mord mathit" style="margin-right:0.13889em;">P</span><span class="mclose">)</span><span class="mbin">+</span><span class="mord mathit">i</span><span class="mop">sin</span><span class="mopen">(</span><span class="mord mathit" style="margin-right:0.13889em;">P</span><span class="mclose">)</span><span class="mclose">)</span></span></span></span>。</p>
<p>现给定两个复数的 <span class="katex"><span class="katex-mathml"><math><mrow><mi>R</mi></mrow>R</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.00773em;">R</span></span></span></span> 和 <span class="katex"><span class="katex-mathml"><math><mrow><mi>P</mi></mrow>P</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.13889em;">P</span></span></span></span>，要求输出两数乘积的常规形式。</p>
<h3 id="-">输入格式：</h3>
<p>输入在一行中依次给出两个复数的 <span class="katex"><span class="katex-mathml"><math><mrow><msub><mi>R</mi><mn>1</mn></msub></mrow>R_1</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="base textstyle uncramped"><span class="mord"><span class="mord mathit" style="margin-right:0.00773em;">R</span><span class="msupsub"><span class="vlist"><span style="top:0.15em;margin-right:0.05em;margin-left:-0.00773em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span><span class="reset-textstyle scriptstyle cramped mtight"><span class="mord mathrm mtight">1</span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span>​</span></span></span></span></span></span></span>, <span class="katex"><span class="katex-mathml"><math><mrow><msub><mi>P</mi><mn>1</mn></msub></mrow>P_1</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="base textstyle uncramped"><span class="mord"><span class="mord mathit" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist"><span style="top:0.15em;margin-right:0.05em;margin-left:-0.13889em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span><span class="reset-textstyle scriptstyle cramped mtight"><span class="mord mathrm mtight">1</span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span>​</span></span></span></span></span></span></span>, <span class="katex"><span class="katex-mathml"><math><mrow><msub><mi>R</mi><mn>2</mn></msub></mrow>R_2</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="base textstyle uncramped"><span class="mord"><span class="mord mathit" style="margin-right:0.00773em;">R</span><span class="msupsub"><span class="vlist"><span style="top:0.15em;margin-right:0.05em;margin-left:-0.00773em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span><span class="reset-textstyle scriptstyle cramped mtight"><span class="mord mathrm mtight">2</span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span>​</span></span></span></span></span></span></span>, <span class="katex"><span class="katex-mathml"><math><mrow><msub><mi>P</mi><mn>2</mn></msub></mrow>P_2</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.83333em;vertical-align:-0.15em;"></span><span class="base textstyle uncramped"><span class="mord"><span class="mord mathit" style="margin-right:0.13889em;">P</span><span class="msupsub"><span class="vlist"><span style="top:0.15em;margin-right:0.05em;margin-left:-0.13889em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span><span class="reset-textstyle scriptstyle cramped mtight"><span class="mord mathrm mtight">2</span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;">​</span></span>​</span></span></span></span></span></span></span>，数字间以空格分隔。</p>
<h3 id="-">输出格式：</h3>
<p>在一行中按照 <code>A+Bi</code> 的格式输出两数乘积的常规形式，实部和虚部均保留 2 位小数。注意：如果 <code>B</code> 是负数，则应该写成 <code>A-|B|i</code> 的形式。</p>
<h3 id="-">输入样例：</h3>
<pre><code class="lang-in">2.3 3.5 5.2 0.4
</code></pre>
<h3 id="-">输出样例：</h3>
<pre><code class="lang-out">-8.68-8.23i
</code></pre>
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