title: How to open a div accordion on button click angular2
body: <p>I have an accordion as shown</p>
  
  <pre><code>&lt;div class="panel-group" id="accordion"&gt;
    &lt;div class="panel panel-default"&gt;
      &lt;div class="panel-heading"&gt;
        &lt;h4 class="panel-title"&gt;
          &lt;a data-toggle="collapse" data-parent="#accordion" href="#collapse1"&gt;
          Collapsible Group 1&lt;/a&gt;
        &lt;/h4&gt;
      &lt;/div&gt;
      &lt;div id="collapse1" class="panel-collapse collapse in"&gt;
        &lt;div class="panel-body"&gt;Text1  &lt;button (click)="Open()"&gt;Apply&lt;/button&gt;&lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="panel panel-default"&gt;
      &lt;div class="panel-heading"&gt;
        &lt;h4 class="panel-title"&gt;
          &lt;a data-toggle="collapse" data-parent="#accordion" href="#collapse2"&gt;
          Collapsible Group 2&lt;/a&gt;
        &lt;/h4&gt;
      &lt;/div&gt;
      &lt;div id="collapse2" class="panel-collapse collapse"&gt;
        &lt;div class="panel-body"&gt;Text2&lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to open the second collapsible panel based on the button click in first panel . How can I do that in angular 2 ?</p>