To take down a tank all by yourself, the best way is C4. It takes 3 C4 to be sure to kill a LAV, tank or boat. Jeeps and Armored transport (Humvees, Vans, etc) takes 2 for a sure kill.
Note that 2 piece of C4 might kill a tank if you put them on the right spot (mostly on it's rear from what I found). If you put two pieces on the sides, it will disable the vehicle and leave it burning giving time to the driver to jump out. If you put the 2 pieces of C4 on the front, it will disable but not put the vehicle on fire.
1 piece of C4 does a mobility hit for sure which can allow you to put more C4 instead of the tank running off.
Mines are also a good way to take care of tanks, but you must place them near it and hope it runs over it (or shoot them with the Rex/magnum/slugs from shotguns) or place them in popular spots for vehicles to get that random kill 5 minutes later.
For the launchers, this is what I found:
Also, I found this forum post:
http://bf4central.com/battlefield-4-rocket-launchers/
For the damage stats versus vehicles per launchers, I could not find the stats. But I've heard that RPGs do the same damage as a tank shell. The angle is (like in BF3) primordial in BF4. If your rocket hits at 50 degrees, it will do around 20 to 25 damage while hitting a tank square on will do a disable in most cases. Tanks are also more resilient on the front to damage. Sides have less armor and even less armor to the rear.
Overall, killing a tank alone is easier with C4 since a good tank driver will rarely get killed by one engineer. However, to maximise your rockets potential, doing a 90 degree hit on the rear of the tank is the most effective way to kill it and the RPG is the one doing the most damage according to what I read.
Also, repair tools work wonders if you can sneak up on the tank, but that usually ends up in a suicide when the tank blows up (in BF3 you could survive with less than 10 HP, but in BF4 even if I stay at maximum Repair tool range, I still die).
Sources not linked before:
http://forum.symthic.com/battlefield-4-technical-discussion/5689-bf4-engineer-launcher-stats/
EDIT: Added mines,also, a guy took the time for 3 of the launchers:
http://www.reddit.com/r/battlefield_4/comments/1q39oy/rocket_damage_to_vehicles/
EDIT: RPG vs SMAW analysis
Best Answer
The China Rising Bomber is deployed from one of the control points that is held by your team on Conquest mode. The trailer you need to enter is a yellow "portable" box with a radar disk on the side. Once you enter it, the system connects you to an inbound bomber which flys fairly quickly across the map. The bomber can drop 4 JDAM bombs and a cruise missile during each "load" and if you're quick you can get two loads per run.
You can click on the ground where the bombs are to be deployed to, however with a 5-6 second flight time they are not suited to moving targets, more likely meant for stationary infantry and vehicles. You cannot control the speed or direction of the plane, but you can deploy a bank of 30 flares to avoid any missiles fired at it.
Once you get a kill you unlock the SUAV for the recon kit, a small, battery powered, remote-controllable plane that can spot enemies, lase targets, and (currently) roadkill as many people as you can hit before the battery runs out.
Once the plane has finished it's run and you exit the command unit, there is a cooldown timer before it can be used again.