sin²(x) + cos²(x)

Yixing knows Chen from all the times he'd crossed the vocal practice rooms on his way to the dancing rooms. He also knows Chen for coming fourth on the Chinese national math competition. He remember his blush when he stood there on stage, unable to shape words because he was so scared in front of the crowd - the entire school watching him receive a diploma congratulating him on the annual National Highschool Mathematics Competitions and inviting to the China Mathematics Olympiad. He stood there on stage looking like he wanted to fall down and hide under the earth and Yixing just really wanted to take him and help him hide. He wanted to hug him so tightly he'd never feel scared again. He wanted to make Chen speak, but only so he could hear, because he loved Chen's voice and he was to be honest very happy he couldn't form any words for the moment so that only a fraction of the school would know how beautiful it was. But Chen wasn't his, he seemed to be Tao's. It was Tao that got Chen to sing, it was Tao that got Chen to laugh and scream when he saw them in the corridors, it were Tao who shared a dorm with Chen and rather openly told people that they shower together because he's scared of ghosts. They shower together in that tiny shower cubicle at the school's dorm. And Chen loved mathematics, he could hear him in his math class, Chen had skipped a year or more, laughing and being overly touchy with Xiumin and cracking up about how second order homogenous differential equations' characteristic equation was romantic, no a stalker as they were making their way outside, and Yixing was failing his class and understood nothing. So when Yixing started to talk with one of his smarter friends about at math, he'd completely forgotten that Xiumin was one of Chen's friends. Which wouldn't really be a problem, his blood didn't boil when Chen and Xiumin were touchy because Xiumin had a boyfriend and he'd never introduced him to Chen or talked about how his 'admiration' for the other was very obvious so Yixing really didn't see it coming when Xiumin called Chen over and ask him how busy he was. Chen was blushing and quiet, probably because of Yixing's presence at the table and answered Xiumin's question saying he didn't really how much to do anymore and mumbling how he quit a lot of stuff Yixing didn't really catch. But Xiumin smiled and introduced Yixing for him, saying he desperately needed help with math. Chen's eyes went as wide as Yixing's eyes since had been since Xiumin called the other over, and Chen stole a tiny glance at him. Before any of them could protest, Xiumin said “great, exchange contact information”, and Chen looked really intimidated by him then, so he took out a small note and started jotting down some numbers. It took a while before Yixing could tear his eyes away from Chen and messily tear out a corner of a notebook and doing the same. By the time he was done he saw a pair of hands shaking before him. When their hands accidentally (at least Chen would like to think that way) met when switching numbers, Yixing kinda sat back by the fact they did it by exchanging notes, both turned even more red and Chen ran away, the note with Yixing's number tightly secured in his hands and Xiumin released the laugh he's been holding back, laughing so loudly they both knew Chen could hear him. “Call him, he'll freak out staring at his phone” Xiumin said as he got up leaving Yixing rather dumbfounded at the canteen. Later that day, Yixing up his pride and texted Chen (it took him hours to find out what the write) rambling about how he hoped he didn't mind helping him, because he really needed the help. Yixing didn't know if it was due Chen's kindness and disability to say no to someone with problems, or because Chen loved math and wanted everyone else to love it too - he'd seen him in the others math class - half an hour later he got a text back asking when he got time.

They decided to meet at the university library that Saturday. As a second year high school student, Yixing had never been there before, but Chen who was supposed to be a first year and already done with his math class took extra courses at the university so he apparently liked the building. Yixing though, was rather stressed about it, so Chen said they could meet at the subway station. So Saturday morning Yixing sat on the train wishing he'd skipped breakfast because he's stomach was turning so much he thought he was going insane. The feeling didn't really get much better when he got off the train and found Chen reading a thick frightening book biting his lower lip deep in thought. His lips were already so plumb and pink… He stood rooted staring at him until another train stopped and he got showed even closer to Chen by the small busy crowd making it's way to the exits. He almost tripped over Chen, suddenly extremely grateful for his dance experience and balance for not making a fool out of himself. Still, the passing crowd made Chen look up and turn a light shade of pink when he saw him. He darted up, his book almost falling out of his hands and started to mutter his apologies for not seeing him standing there and questioning just how long had he been there. Yixing was rather set back by the huge amount of words suddenly dropping out of Chen's beautiful feline lips. For a split second Yixing could see him with cat ears fluttering around in distress and a tail barely making it out between his tightly closed legs. The thought made Yixing cough by the warmth pooling in his lower regions, and he told Chen it was no problem and uncomfortable proposing that they got a move on, because he really didn't want to stay there for yet another train unload another pack of spectators when his pants was on the border to feel tight by just watching the other fumble. Chen seems to remember that that was in fact why he's standing in front of him and mumbles a shocked “yes, yes – of course”. They walked quietly side by side until Chen seemed to be tripping over something Yixing have no idea how he managed to be so clumsy, but he catches him with all of Chen's weight leaning down on one arm and their bodies closely knitted and holds him tight until he realises their position isn't something you keep up and helps Chen straighten himself. When Chen almost stumbles again as he tries to stand he finds it only logical to keep his arm wrapped over Chen and promise himself it's not an excuse to keep holding him close and catches some of Chen's mutterings of gratitude and embarrassement.

There wasn't a long walk left to their destined building an Chen mutters an explaination of that this is the science library and that the main library is the building the passed over there. Chen takes seat right next to him sliding close as it's Yixing's turn to fumble, getting his books. Then, when Chen asks him what he needs help with, he stares down at the papers and let “everything” fall down from his lips so low he hopes Chen doesn't hear it. Much to his suprise he is rewarded with a small chuckle and Chen asks “how about if we start with the first chapter?” and Yixing finds himself nodding, not able to tear his eyes of the papers.

Yixing listens to Chen's voice for hours, and he realises as he notice that the sun's setting both that and that it is actually starting to make sense to him, the sine and the cosine and the exact values, he starts to understand what they are. Chen laughs by hearing Yixing muttering the last part and smiles, saying “mathematics isn't all that scary once you understand what all those mathematicians actually mean and talk about” and he finds himself nodding slowly.

◊

It's been a week and his math class has completely discouraged him from his study session, but he promptly gets of the train and walks to the library. When he gets there he finds Chen buried in books and paper, and he only makes out stuff like Wronskian determinant and that it's maths he hope he never has to learn. He sits down next to him and Chen doesn't even notice until he pats his shoulder mumbling a hi. Chen jumps, a few papers almost flies off the table but Yixing is quick to catch them. Chen mutters a low thanks and it's suddenly Yixing's turn to chuckle and he apologises for scaring him and Chen shakes his head explaining he gets caught in his own thoughts sometimes (more like all of the time, but Yixing doesn't interrupt and voice his thoughts). Chen finishes explaining chapter one and lets him try do some of the assigments and tasks but Yixing soon find him staring at Chen biting his pencil and occasionally jotting down some notes next to a proof about Euler's algorythm or something Yixing has no idea what is, to ashamed to ask Chen for help when he's already stuck on the second question. After a while, Chen seems to realise Yixing isn't writing so he looks up and Yixing flushes being caught redhanded being a stalker like weirdo. Chen laughs, much the Yixing's surprise and he lifts his eyes up again to only be blended by Chen's beauty. Chen pushes is big, black glasses back on his nose and Yixing wonders how they'd looked stained with come and he flushes coughing like he's choking and Chen's petite hands hitting his back isn't really helping his over-sensitive state. When his coughing dies down, Chen asks him if he needs help, and Yixing nods, and somehow it ends with Chen showing him how to solve any kind of question and marking endless pages of Yixing's notebook with notes as beautiful and petite as Chen himself, always matching the size of his writing with the tiny squares in his book, his handwriting so beautiful Yixing has a hard time believing it's actually a boy next to him writing. Yixing looks up at Chen just to confirm it and sees Chen shining in the soft light of the sunset and a librarian informing that they will close in ten minutes. Chen looks up and smiles at him, “I'll finish this and then we can pack up?” and Yixing stares at him nodding. Chen is finished in minutes and with a feeling Yixing can only label as sadness, he follows Chen's example and starts to pack up his stuff. Just like he's noticed before in class, Chen is extremely slow and the librarian is soon back sighing and rolling her eyes at Chen, who sheepishly smiles and bows. It really doesn't seem like this is the first time she's caught him before she almost locked him in the library to the next morning.