After Erin's affair was over, and everyone sat down around the campfire again, Rosen asked curiously, "Veronica, so you just hid behind a tree?" ”

Veronica knelt beside the campfire, staring at the bonfire without blinking, her face was as cold as the snow and ice of dog days, as if Rosen owed her a hundred thousand silver rontes, and when she heard Rosen's words, she whispered, "No, I was attracted by the loud sound of the Doomsday Iron Ball." I had just arrived when Irene fell to the ground. ”

Rosen asked again, "Oh~ If you had arrived earlier, would you have stopped Erin from killing me?" ”

Veronica thought for a moment and replied, "I...... Not sure, maybe, probably not, depending on how I was feeling at the time. ”

Rosen smiled: "Then it's a good thing you're a little late." ”

After saying that, he saw that Veronica's face was even colder, and he knew that the other party must be in an extremely unhappy mood, especially for him, there was definitely a huge dissatisfaction.

Such a state is likely to cause her to be passive and slack, if she is negative, Rosen will not be able to trust her, and the terms they have negotiated will be reduced to empty talk.

He had to find a way to ease the relationship.

After thinking about it, Lawson took out a piece of parchment from his waist bag, picked up a slender piece of black charcoal from the campfire, quickly smeared it on the parchment for a while, and then handed the parchment to Veronica: "Here you go." ”

"What's that?" Veronica was stunned, but took the parchment anyway, and when she glanced at it, her eyes were drawn to the contents.

After watching it for more than ten minutes, she raised her head, and the coldness on her face had all turned into incredulity: "You actually calculated the formula for the volume of the sphere, which ...... What a miracle! ”

Rosen smiled slightly: "Isn't the method ingenious?" ”

Veronica seemed to have completely forgotten the previous unpleasantness, she was immersed in the world of mathematics, and her eyes carefully watched the parchment deduction process: "That's true. I can see that you're borrowing the concept of 'limit' again. Previously, you used a similar method to calculate pi using circumcision. ”

Lawson nodded: "That's true." I found the concept of 'limit' very interesting. I have a hunch that by extending and developing the concept of 'limit', it is even possible to deduce a whole new branch of mathematics. ”

In fact, this branch is calculus, a mathematical tool invented by Lord Niu and Leibniz at about the same time, and is one of the greatest achievements of human intelligence.

Suffice it to say, calculus is the most important key to the world of modern science, and it cannot be overstated.

Hearing this, Veronica was completely confused, and the gaze that looked at Rosen was no longer half cold, but became extremely eager, and even a trace of worship.

"Rosen, you have wisdom that is hard for ordinary people to match, and I believe you will be able to do it."

As soon as she finished speaking, Annie's soft cough came from the side: "Veronica, whether you believe it or not, Rosen can do it!" ”

These words woke up Veronica, she realized that she was out of shape, her face suddenly became very cold again, she glanced at Lawson coldly, and snorted: "Don't try to seduce me with mathematics. From now on, I won't say anything more than to keep you safe! ”

Rosen shrugged his shoulders: "As you wish." ”

After being quiet for a while, he took out a piece of parchment from his waist bag and said to Anne beside him: "Anne, come here, let me tell you, I have not only calculated the formula for the volume of the sphere, but also the formula for the surface area of the sphere." It's very interesting for you to come and see. ”

Anne has learned a lot from Rosen this month, especially when she saw the power of alchemy, she attaches great importance to mathematics, and she learns very quickly, and now she can understand some simple mathematical deductions.

She glanced at the parchment, and her eyes lit up: "This is the formula for calculating surface area?" It's so easy. ”

"Haha~ Although the result is simple, it is not easy to calculate. Look here, for ......" Rosen said, his voice getting softer and softer, until at last he leaned into Anne's ear and whispered to her.

Veronica had been eavesdropping with one ear, but she couldn't hear at once, but she was very curious about the sphere surface area formula. In fact, she had thought about the surface area of the sphere before, but no matter how she calculated it and how she deduced it, she could only get approximate results.

Now, Rosen has a precise calculation formula at hand, but she can't see it, she only feels like an ant crawling in her heart, tickling her heart, but she can't get it, not to mention how uncomfortable it is.

Finally, she couldn't help it anymore and said angrily: "Rosen, don't go too far! ”

Rosen raised his head and said in amazement, "What's wrong?" Didn't you say don't use math to seduce you? ”

"You ......." Veronica was speechless for a moment, but her face was very cold, like the cold wind of the wax moon, and it was about to explode.

Rosen accepted it when he saw it, and hurriedly said, "Veronica, you are a very trustworthy person. The last time you went to great lengths to retrieve the griffin acid sac for me, I was convinced of that. ”

Veronica's face softened slightly: "Count you as acquaintances!" ”

Rosen continued: "You see, we have made a contract. I'll let Erin go, and you'll keep me safe. You're not going to break your promise, which means we're going to have to be together for at least forty or fifty years, right? ”

Veronica took a deep breath and nodded slowly, "Yes! ”

"However, you have been keeping a cold face, and the atmosphere is so stiff. It's so uncomfortable to live like this for decades. Lawson spread his hands with a helpless expression.

"What do you want to say?" Veronica heard something.

"What I want to say is that just because I want you to sacrifice your freedom to protect me, I must have wronged you, and I have taken a big advantage."

Veronica's face changed a lot: "You still have a little conscience!" ”

"So, in order to compensate for one or two, I assure you that you have priority to know any new results, even new ideas, that I have in my lifetime, in mathematics, what do you think?"

This sentence hit Veronica's soft underbelly at once. In fact, she was finally able to agree to Rosen's conditions, in addition to her friend Erin, vaguely, she also had the intention of stealing mathematics from Rosen.

Now, Rosen has picked this out, and is speaking to her secret thoughts.

"Really?"

"It's true, high-five!" Lawson held out his hand.

"Smack~" Veronica reached out and touched it, and then stretched out her hand to Rosen: "Show me the parchment in your hand." ”

Rosen laughed and handed over the parchment.

As soon as Veronica got the parchment, she went to look at the formula, and when she saw the formula for the area of the sphere, she compared it with the approximate formula she had deduced, and then let out a long sigh: "It's so simple and subtle, it's beautiful." ”

It's like drinking a sip of a sweet spring in the desert, and it's indescribably beautiful.

Then she went back to see the deduction, and the more she watched, the more fascinated she became, until at last she was so engrossed in the parchment that she was completely oblivious to the movements of the outside world.

At this time, if Anne secretly shot her in the back, she would definitely fall in response.

Seeing her like this, Anne leaned into Rosen's ear and whispered, "Well, I can see that this woman is a nerd, no wonder you are reassured of her." ”

"Hey, hey." Rosen smirked.

Anne's tone changed: "However, the look in her eyes is obviously wrong. I have to warn you, she's a very powerful monster of unknown origin, don't mess with her, she'll kill you. ”

Rosen scratched his head, slightly embarrassed: "Annie, you think too much. ”

Beautiful people, appreciate it, human nature, he will stop here, he still carries this clearly.

"I hope so."

Anne sighed, she rolled up the thick bear skin, and curled up on the ground: "I slept, and I have to hurry tomorrow." You should rest early, too. ”

"yes, okay." Rosen also rolled up the bearskin and lay down against Anne's hot body.

Nothing was said all night.

Early the next morning, Lawson opened his sleepy eyes and looked at the tree next to him, only to find that the high-level vampire Irene was nowhere to be found.

"Don't look, she's gone."

Veronica's voice came from beside her.

Rosen turned his head and saw Veronica writing and drawing on the dirt floor with a twig in her right hand and parchment in her left hand.

"You haven't slept all night, have you?" Rosen exclaimed.

Veronica smiled slightly, "I can stay awake all the time if I need to." As for sleep, when I'm bored, I close my eyes and take a break. ”

Lawson listened to it with a smacking tongue, and he could even save sleep, which was really amazing.

After that, Sister Mary and the others also woke up, and Lawson took out the meatloaf and dried fish, divided one by one, and then announced: "From now on, Veronica will walk with us." ”

Sister Mary was now completely numb to the miraculous thing that had happened to Rosen, and she just responded with an 'oh'.

Little Alice looked at Veronica and praised sincerely: "Sister, you are so good-looking." ”

A simple sentence made Veronica feel good, and she gently patted little Alice's head: "It's still a little girl's eyes." ”

After speaking, she glanced at the meatloaf that Lawson gave her with disgust, and wanted to throw it away directly, but her stomach was a little hungry, and she couldn't do it, so she took a small bite lightly, chewed it a few times, and her eyes lit up: "Lawson, what good things did you add to it, and it tastes so fresh?" ”

"A kind of alchemy item, non-toxic, the effect is to improve freshness, how about it, not bad?"

Veronica nodded again and again: "Hmm~ It's really a good thing." When it comes to Berkeley, this umami elixir alone can be sold for a lot of money...... But speaking of the Free City...... You're heading all the way north to Berkeley, aren't you? ”

The question was a bit sensitive, and Rosen and Anne looked at each other, and Anne said, "If you believe her, just tell her, maybe she can help." ”

Lawson pondered for a moment and said, "Actually, I went north this time to detoxify. ”

Veronica was taken aback: "Detoxification? You look alive, don't you look like you've been poisoned? ”

Lawson lowered his voice and said in a volume that only three people could hear, "It's vampire poison, also known as blood seal magic." A gift from Viken. ”

As he spoke, he pulled down his collar, revealing the healed scar on his neck.

After seeing the scar, Veronica patted her forehead and said distressedly, "Rosen, I'm afraid you're going to be disappointed." ”

Rosen was stunned: "What do you say?" ”

"As far as I know, the magic of the undead can only be unlocked by the undead. This blood seal magic in you can be solved either by the caster himself or by the caster's Ancestral Elder. There is no third option other than these two. ”