Defining and dividing the zodiacal constellations, Tianzhu and the Central Plains use the moon phase method.

It is also compared to the relative change of the position of the moon in a sidereal month, which is the ecliptic domain.

The so-called sidereal month mentioned here is the real cycle of the Moon's orbit around the Earth with the star as a reference.

A sidereal month is about 27.33 days, so there are pros and cons to choosing whether to divide the day into 27 or 28 zones.

In the same way that the West uses the heliographic method to divide the ecliptic, taking 12 houses between 12 and 13, this difference is always there.

The method adopted in ancient China was to use 28 stars as a reference to divide them, and not to do mathematical equal divisions.

On the observation instrument, it must be fitted by the aliquot method.

But Gu Tianzhu adopted the same method as the West, since the extra one can't be made up, then simply remove it, and only take 27.

I don't know if it's because of a coincidence, or out of the need for faith, the star that was specially filtered out by Gu Tianzhu is the Ox Sutra among the 28 Nakshatras.

Tianzhu acknowledges the existence of a gap in the 27 Nakshatra sub-domains, and defines this gap as the Black Sky Victory Domain, which is the zodiacal sub-domain where the moon resides when the legendary Hindu god Black Sky was born.

The Black Sky Triumph is only one-third of the angle of a normal constellation in the ecliptic, but it is the shrine of the moon.

The other 27 nights are the wives of the moon, and the moon is lucky every month, and it sounds poetic to turn around in room 27.

However, this poetic partitioning method limited their development of observation instruments, and stargazing instruments based on the 27th square of the ecliptic never appeared.

The drawbacks of the Tianzhu star calibration method were mentioned by a child, and the face of the holy minister was naturally not very good-looking.

In order to get back on the field, he began to try to cover up the problem with mathematical knowledge.

"There is nothing wrong with Tianzhu's division method.

We have mastered the meaning of the calculation of the circumference ratio,

By calculation, it was possible to divide the sky dome into 27 parts with great accuracy. ”

The circumference ratio of a circle, in the original is called pi.

Liu Xin of the Western Han Dynasty and King Fan of Wu during the Three Kingdoms period once tried to accurately calculate pi by using the method of turning the circle into a square.

The so-called square is to use the square to fit the area of the circle and then reverse the circumference ratio of the circle.

This method is not very accurate, and the value calculated by both people is around 3.15.

However, since Liu Hui invented the black algorithm of circumcision, using the idea of calculus to calculate the area of a circle,

The problem of pi has been completely solved in China.

The rest of the work is the number of actuarial fits, which is the problem of extrapolating this value to the nearest decimal place.

Liu Hui himself was "relatively lazy", he only calculated the area of the inscribed 96 sides of the circle, thus pushing the pi to 3.1416.

But Zu Yuzhi's father, Zu Chongzhi, is a ruthless person, he counted the 24576 side in one breath, and pushed the accurate value of pi to seven decimal places.

This record has been proud for more than a thousand years, and there is no rival.

In fact, from a methodological point of view, as soon as Liu Hui's circumcision appeared, China had already won.

In fact, even in complex modern calculations, it is rare to really use so many decimal places of pi, and in most cases 3.14 is sufficient.

This is the sparse rate given by Zu Chongzhi - twenty-two out of seven.

In the production of the armillary sphere, each area of the four elephants needs seven points, and the expression of fractions with seven as the denominator is also conducive to the calculation of armillary sphere stargazing.

However, although the problem of pi has long been successfully solved in China, this number is endless after all, and it cannot be absolutely actuarial, and it has always been a difficult point in arithmetic.

Maybe Tianzhu really has a better way to express it for reference?

At this time, not only Xin Dufang, but even Zu Yuzhi and Tao Hongjing pricked up their ears.

The Shengchen was full of confidence, saying that Tianzhu had recorded the estimation of pi in the White Night Rou Yu as early as the Sixteen Xiongguo periods, and still used the ancient method of turning the circle into a square, and the final value was about 339/108.

This value is indeed sufficient for the calculation of the circumference, and is much more accurate than the estimate of the third diameter of the Chinese Monday in the same period.

However, after these hundreds of years, Tianzhu is still obsessed with the backward algorithm of imitating a circle with a square, which fundamentally cannot solve the problem of pi.

Xin Dufang was a child, and he didn't know the wording of diplomatic occasions, so he immediately pointed out the backwardness of the Tianzhu algorithm.

Calculation is one of the areas of expertise that Shengchen is most proud of.

At this time, he was teased by a child like this, and he was a little upset, so he got up with Xin Dufang at that time.

Xin Dufang was not ambiguous, strode into the school, and used the branches as the pen and the yellow sand as the paper, and explained the circumcision and Liu Hui's calculation formula on the spot.

Shengchen is naturally not a mediocre person, his ability in arithmetic is second to none when he looks at Wutianzhu.

Therefore, Xin Dufang explained a little, and he could hear the wonderful use of this rounding.

At this time, he had completely gotten rid of his initial arrogance, listened carefully for a while, and then began to ask and answer questions with Xin Dufang and interact.

In arithmetic, sometimes discovering a new idea or a new method is equivalent to opening up a new world and a new world.

The door has always been there, but opening it or not opening it is the difference between the moat and the pathway.

Two years later, the revitar completed his Almanac of Ariahatta,

Tianzhu's pi calculation has entered the era of the fourth decimal place.

At the same time, the Saint used the word āsaa to show that his calculations were not precise enough.

Many Indian scholars have been complacent for many years, believing that this word of the Prophet proves his knowledge of irrational numbers.

In fact, this was only because he knew that the accuracy of his calculation results was far inferior to the density ratio used by Nakahara at that time, so he called his calculations approximation.

As for the term irrational number, it was originally the definition of the West.

Although this concept was not explicitly proposed in China or ancient India, it was recognized as early as the Liu Hui period that there were numbers that could not be fully fitted.

When calculating pi, Liu Hui said: cut the fine, the loss is small, cut and cut, so that it cannot be cut, then it is combined with the circumference and there is nothing lost.

This sentence is the true meaning of "approximation" in mathematics.

The infinite approximation algorithm of opening square and opening square has been formed in the era of "Nine Chapters of Arithmetic".

Most of the Chinese arithmetic scriptures are pragmatic and solve the problem of how to calculate, without putting forward too many concepts and theorems like philosophy books.

Arithmetic, although it enters the six arts, it ranks last, it is a strange skill, and it does not enter the mainstream Taoism.

Therefore, it is advisable for books and biography to be practical, if they are too theoretical, they will be like the ancestral secret book "Fixation", which will end up with the same skill as the dragon slayer.

The holy minister was folded by Xindu Fang, and after talking about it, his attitude immediately changed greatly.

He intended to rebuild the calendar for Tianzhu, so he asked Xin Dufang for many details of the Central Plains calendar.

At that time, the laws of the Tianzhu calendar stood side by side, and the system was complex, with the sun, the yin, and the lunisolar calendar coexisting.

The Central Plains calendar combines the strengths of the calendars, has been decided, can be relied on to know the hope, when the agriculture is broken, the functionality is strong, and the holy ministers can't help but be amazed.

The holy ministers came to Middle-earth, and the envoy of the young king was certainly one of the purposes.

However, as far as he is concerned, being able to learn from everyone in the Celestial Empire is also the main reason why he is willing to serve as this chief envoy.

He saw that the children of the Central Plains could have such attainments in arithmetic, astronomy, and calendar, so he knew that this trip would be very rewarding, so he asked tentatively,

"Brother Xin's insight is really good, but I don't know who taught these knowledge?

The Central Plains is in arithmetic, who are you, can the little brother recommend it on your behalf?

I have the intention of learning, but I don't know immortals.

Jingwa cries lonely, where can you see the sky? ”

The last few ancient style five words are naturally not the original of the holy ministers, but the Shu merchant Gongsun Qing saw that the soft power of the Central Plains was greatly promoted, and his heart was very uplifted.

Although the south of Shu belongs to the Qi country, the red flowers and green leaves are always one, and the cultural background of the northern and southern dynasties is the same.

So she got carried away with joy, and casually translated the humble words of the holy minister into a song.

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