Seeing that the woman was about to cry in a hurry, Ruyu kindly reminded her: "What you just said was wrong, it's not that sin180° and cos360° can be omitted, so you deduced sin25° and cos35°."

You say that your answer is correct, you see, in the case of sin25°cos35°+cos25°sin35°, you all know that they together are sin(25°+35°).

On the other hand, splitting the parentheses is naturally sin and cos are also linked together, so why did you come to the idea that sin180° and cos360° can be omitted so hastily? ”

Seeing that the woman was still a little ignorant, Ruyu continued: "That is to say, the sin (180°-25°) in front of you, it is not ignored, and the trigonometric formula is different from the ordinary number formula.

To be correct, sin(180°-25°)=sin180°cos25°-sin25°cos180°=sin25°, instead of ignoring sin180° and getting sin25°. ”

The woman suddenly realized, looked at Ruyu with a grateful face, and said a little embarrassedly: "I haven't touched these for a long time, and I forgot about it for a while." ”

Ruyu smiled back, "I haven't been in a long time—"

Suddenly, her heart beat heavily, and a thick sense of abruptness came to her heart.

Yes, she hasn't touched it for a long time, and her major is interior design, and it doesn't match mathematics.

She remembered that she only scored 54 points in mathematics in the college entrance examination, and she had forgotten these trigonometric inducing formulas a long time ago.

So, why did she just glance at the question and make the solution process clear?

Ruyu clenched her hands slightly and said, "Can you lend me a pen and a piece of paper?" ”

The boy gave her a lot of face, blinked his eyes, handed her a pen and paper, and said, "Sister, you are so good-looking." ”

Ruyu wanted to laugh, but she couldn't laugh at all now.

Picking up the pen, she directly dictated π.

She is extremely sure that in high school, including college, she will never forget the number concept of π only π=3.14159.

However π in fact, there are still many numbers in the follow-up, and there have been friends who deliberately write π more than silently, and whoever writes more silently wins.

Ruyu didn't participate in this game at the time, two words: she was lazy.

Being able to memorize the π to 3.14159 is considered to give π face, which is still often remembered by listening to the chatter of the same table, otherwise she will memorize the commonly used 3.14 at most.

It's just that at this moment, the moment she puts down the pen, the follow-up about π jumps in her heart like a note, and the pen is like a god.

“π＝3.1415926535897932384626 43383279502884197169399337510 5820974944 59230”

Writing this, Ruyu suddenly put down the pen, and a blank look crossed her eyes.

Once again, she was sure of one thing, as long as she wanted, she could write more than a hundred numbers in the future, and it seemed that there was an infinite memory bank in her mind.

She...... What's going on?

Why are there so many things all of a sudden?

Next to him, the prince said happily: "Sister, you are so amazing, you can write so long, I can't write up to ten numbers at most!" ”

The woman in professional attire also looked at her with admiration, stars in her eyes.

But Ruyu didn't feel happy at all.

She just wanted to say something about it now.

When did she become so awesome, even she didn't know!

The little boy jumped up and grabbed her hand: "Beautiful sister, I want you to be my teacher!" ”

The mood of jade gray gray has been slightly dispelled, no matter where she praises, it can make people feel happy, although she prefers others to call her handsome young lady~

"You've already learned trigonometry, it's high school knowledge, and my education level is not enough to teach you."

The boy was a little ignorant when he heard this, blinked his eyes and asked, "Sister, don't you know this knowledge?" ”

Ruyu really wants to say no, but you can't be a conscience.

Especially just now she also showed off a handful of knowledge points, well, so she has a good conscience.

"I will."

The boy jumped up again with joy: "Oye, I want my beautiful sister to teach me!" ”

The front desk seemed to see Ruyu's embarrassment, and said in a low voice: "Prince, this sister has other things to do, and she may not have time to teach you." ”

Ruyu's eyes flashed slightly, wait, prince?

The boy frowned and said aggrievedly, "But I just want her to teach ......"

Ruyu smiled slightly: "Okay." ”

The front desk was softly comforting the young man: "Prince, this sister has something to do when she comes to the company, and you have something at home-"

Suddenly, she was stunned, looked up at Ruyu, and the boy also looked over.

Ruyu said calmly again: "Okay, I'll teach you." ”

"But-" she changed her words, "it's not unconditional to teach you, I'll give you a few questions, you can do it, let me see where your level is, it's too bad I don't want to teach." ”

The boy cheered, and he chose to skip the latter sentence, only remembering the previous one, "My sister wants to be my teacher!" ”

Ruyu: "You have to complete the question first." ”

The boy grabbed her hand, "Come, I'll take you to my house to see, my sister is going to come to tutor!" ”

Ruyu: "No, you do the set of questions first." ”

The boy dragged her forward vigorously: "Sister, run faster, why are you so heavy, I can't pull you!" ”

Ruyu: "......"

Tsk, it's really a bear child.

She can't provoke the bear child even if she is fierce.

The treatment of the prince is extraordinary, as soon as he leaves the company, there will be a special driver to pick him up, and he can go wherever he wants.

Ruyu asked some boys about their studies in the car, and also knew a little about his family situation, his name is Zhong Mufan, and he has an older brother Zhong Muling, who is 20 years older, and he is the son of the boss of Shiyue Records.

His elder brother Zhong Muling is very powerful, he became a university professor at the age of 30, studied for a double degree in physics and biology, and usually attended classes and then soaked in the laboratory to do experiments.

According to Zhong Mufan, his brother is conducting a great experiment that, if successful, could change the lives of human beings!

Ruyu is not very interested in this, this world has the same background as the world she originally stayed in, and she really wants to invent a cross-era product, and the accumulation of this world is still not enough.

At least their artificial intelligence here is very backward, and AI has not been popularized in mobile phones.

She was more interested in Zhong Mufan, a ten-year-old boy who showed an outstanding talent in mathematics and was already able to understand the knowledge points of high school at a young age.

Give him a little more time, and I'm afraid he will be able to study calculus.

This is the only real genius boy she has ever come into contact with.

……

The sun seems to be particularly fond of this villa, and the fine sunlight shines through the layers of leaves, leaving golden spots on the ground.

At this time, it was the afterglow of the sunset, and when Ruyu got out of the car, she saw a young and handsome man with his back to the sunset, holding a kettle and patiently watering the flowers in the grass.

The man wears a white shirt and trousers, the simplest style is to wear a chic and calm taste, and the sky behind him is a magnificent and colorful fiery cloud.