It looks like homework, so read this:
But the question didn't actually ask you to plot it, so I can do that part for you:
fprintf('Beginning to run %s.m ...\n', mfilename)
x = linspace(0, 12, 1000);
f = 8 * sin(x) .* exp(-x) - 1;
plot(x, f, 'b-', 'LineWidth', 3);
title('8 * sin(x) .* exp(-x) - 1 vs. x', 'FontSize', fontSize);
xlabel('x', 'FontSize', fontSize);
ylabel('f', 'FontSize', fontSize);
ax.XAxisLocation = 'origin';
ax.YAxisLocation = 'origin';
g.WindowState = 'maximized'
fprintf('Done running %s.m.\n', mfilename)
If you need help with your Newton Raphson code, please post that. We're not just going to hand it over to you since it's your homework.