Answer
$1900$ dollars.
$1,805,000$ dollars.
Work Step by Step
Step 1. Given $R(p)=-\frac{1}{2}p^2+1900p$, let $a=-\frac{1}{2}, b=1900$, we know that the maximum of $R(p)$ happens when $p=-\frac{b}{2a}=-\frac{1900}{2(-1/2)}=1900$ dollars.
Step 2. The maximum revenue is $R(1900)=-\frac{1}{2}(1900)^2+1900(1900)=1,805,000$ dollars.