title: I no longer view online equations at RMarkdown
body: <p>I've been working on a document for some time and I was normally viewing latex equations in the R Markdown environment with <code>$Spr = i_ {apl} - i_ {cap}$</code> as <code>$$Spr = i_ {apl} - i_ {cap}$$</code>. But suddenly he stopped visualizing.</p>
  <p>I have already adjusted the settings for viewing and I still can't.</p>
  <p><code>$Spr = i_ {apl} - i_ {cap}$</code></p>
  <p><code>$$Spr = i_ {apl} - i_ {cap}$$</code></p>
  <p>I can't see either in line or in poup-up</p>
  <p>Visualization has been unstable for some time, but then stopped completely.</p>
  <p>I suspect it occurred after some package updates.</p>
  <p>Could someone help me with this issue.enter image description here</p>
  <p><a href="https://i.stack.imgur.com/2JCIT.png" rel="nofollow noreferrer">enter image description here</a></p>
  <p><a href="https://i.stack.imgur.com/ZORTJ.png" rel="nofollow noreferrer">enter image description here</a></p>