How to plot a transcendental equation in matlab (R2017b)?

Here are the constants/variables:

smaje=1.496*10^(8);
ecce=0.0167;
smine=smaje*((1-((ecce)^(2)))^(1/2));
xearth=[-smaje:10:smaje];
earthpos=((smine^2)-(smine^2).*((xearth.^2)./(smaje^2))).^(1/2);
th=(0.1383561324)*pi/2;

Now here is the problem: I want to plot to plot the following equation on a graph:

earthpos.*(cos(th))^2 = (((((smine^2)/(smaje^2)).*(smaje^2-(xearth*cos(th)+earthpos*sin(th)).^2)).^(1/2)).*cos(th)+xearth*cos(th)*sin(th));

earthpos contains the y-coordinates while xearth contains x-coordinates.

[Walter Roberson]

Do you mean that you want to put a marker at -16222020, 148697134.657321 which is the approximate location of where

earthpos.*(cos(th))^2 == (((((smine^2)/(smaje^2)).*(smaje^2-(xearth*cos(th)+earthpos*sin(th)).^2)).^(1/2)).*cos(th)+xearth*cos(th)*sin(th))

is true?