im new to the MH series, MHFU is actually the first of the series ive played so far and i was wondering if anyone had any tips for me on taking out tigrex and rathalos/rathian.

Tigrex - Use Eager Cleaver, stay to one of his extremes and attack from behind after he charges past you.  Don't stay close to him when he roars and bring plenty of traps so you have time to cut his tail off.

Rathian - Use Anvil Hammer, triple pound her head when she does a fire ball and super pound her whenever she turns.  Try not to stay in front of her when she charges and note that when she does her somersault attack, her tail actually sways a bit to the her right/your left, so stay to your right/her left.

seriously, if this is his first tiggy/rath, he isn't gonna have any of those weapons( 'cept khezu shocky).

Rathian: Highest raw powered gs you have. Or, if you like hammers like i do, dynamic hammer/high raw hmm.

When using gs, after her charge run up behind her and start charging the gs. DONT BE GREEDY!!!! If she turns to you, let go. Don't wait for l3.

Rathalos: same stuff, but remember  that he stays in the air a lot, and he will charge like no tomorrow.

Tigrex: Once you're familiar with rathian and have some good armour, download the quest laurel please. You'll go up against really weak rathian shogie and lala(not at the same time) and you should get a rathian spike. Then make golem blade--> golem blade+ --> valkyrie blade --> sieglinde.

Sieglinde has 912 raw power and good green sharpness. This is a godsend against tiggy.

Im surprised no one mentioned this. But its alot easier to kill rathian if you cut its tail off. If the tail is cut off you wont get hit by its tail flip unless you are directly under it.

Oh yea and i recommend devil slicer for rathian and  thunder sns for tigrex. but thats just me.

rathian is more bent towards areas 6 and 4 those are her two main areas i find. where rathalos is like a watchman he's all over the place area 3,4,6 and can be in 10 as well hes a bit harder to pin down.