Push Smartphone Screens to External Device

Why?

Many time I’m listening to a video and my mind wanders as a result of what I hear. I would like to check something that came into my mind, then until the browser downloads the content and renders it, I would also like to jot a short note. I can’t do it today not only because multitasking on smartphones is not very good (or doesn’t exist), but the screen is too small to see it all.

How?

Push the display to an external large screen device like a TV or monitor, a laptop etc. because of the large screen it could be split up and showing multiple apps’ output.