The Ming army replenished supplies in Suzhou and Hangzhou, and the 200,000-strong army sailed towards the South China Sea.

Because Lu Ning and Zhu Di had a good personal relationship, the entire army was well-trained, and there was nothing to do on the ship.

So, he came to Lu Ning's capital ship, but found that Lu Ning was teaching Zhu Xiongying algebra knowledge.

Because all the Arabic numerals and Western symbols were used, it was quite troublesome to write with a brush, so Lu Ning made ink from the solid ink he brought with him and taught Zhu Xiongying hard pen calligraphy.

Zhu Xiongying is also quite smart, and he quickly entered the door, and because of his foundation in ancient arithmetic, it is effortless to learn algebra.

Soon learned trigonometry, exponential functions, and logarithmic knowledge, and even Zhu Di listened to it with novelty.

It's just that what he is best at is war and politics, and he is not very keen on mathematics, Zhu Xiongying asked with wide eyes.

"Master, what's the use of us learning this trigonometric function?"

Now he has mastered the four most basic trigonometric functions: sine, cosine, tangent, and cotangent.

Lu Ning asked him: "Do you know the relationship between how many degrees the angle of inclination of the cannon is and the firing range?" ”

Zhu Xiongying looked puzzled and said.

"Please give me advice."

"In fact, the horns of the cannon and the impact point of his landing can form an isosceles triangle, and the angle of the top angle can be found according to the angle of the cannon."

Hearing Lu Ning talk about the knowledge of cannon shooting, Zhu Di's attraction was also concentrated in an instant, lest he miss something, and begged Lu Ning to talk about it again, and then talk about it again.

"Then according to this formula: the square of the base edge is equal to the sum of the squares of the two equilateral sides minus the product of the two equilateral and elevation cosine. And then square this product, which is the range. ”

Seeing that Lu Ning drew a sketch of shooting on the practice paper, Zhu Di was also very interested, and he also used a quill pen to draw a tiger like a cat, and he also drew one himself.

Then he studied the geometric principles given to him by Lu Ning with relish, and the more he studied, the more he felt that he could use it.

If you had known this knowledge, you would not have been so constrained in the use of artillery when you were in war.

While teaching them some theories of war, Lu Ning did not forget about military affairs.

Leaving the familiar West Sea Island, and continuing south, this part of the area can only be seen in some sporadic records.

Even if there is knowledge of the afterlife, if you are not there, you will not know the specific sea conditions.

He had to send out scouts first, driving in front of the light boat, with a long iron anchor to find his way.

This kind of iron anchor is tied by dozens of zhang of iron chains, and below is a large iron claw weighing dozens of catties.

It can not only be used to fix ships in the river and sea, but also to detect whether there are reefs in the sea and whether the ship will be sunk.

Thinking of doing these jobs by himself, Lu Ning sighed helplessly, he still suffered the loss of backward science and technology.

If there is Beidou navigation and some sonar detectors, why should I be so cautious.

Seeing that Lu Ning assigned tasks in an orderly manner, and seemed to be familiar with all kinds of military details, some veterans such as Xu Da and Tang He couldn't help but nod secretly.

If time passes, this son will be able to become the mainstay of my Ming Dynasty, and the future life will be terrifying!

Lu Ning did not rely on himself because he was the chief general of the three armies, and from time to time he discussed with these veterans some basic principles of marching and fighting, and asked for their opinions first when making any decisions.

Therefore, these veterans are also supportive of any orders from Lu Ning, even if they have different opinions, they will talk to him in private, and they will never contradict him in person.

At this time, a thousand households named Ma Feilong under Xu Da stepped forward and hugged his fists and said.

"General, why do you use some new generals in arranging the vanguard guard this time, do you look down on us veterans?"

Lu Ning knew that this Ma Feilong was a fierce general under Xu Da's subordinates, and he was not below Lan Yu in terms of personal force value alone.

What he lacks is that he doesn't have the talent to coordinate everything like Lan Yu, so even though he has experienced a hundred battles, he is only a thousand households.

But this person's qualifications are also old, and he naturally can't take his kind of questioning lightly.

"Why did General Ma say this? The generals sent this time in the evening are all experienced soldiers who are familiar with naval warfare, and with their guarantees, we can walk smoothly in the unknown seas. ”

Ma Feilong hugged his fists and said.

"The last general is willing to lead the scouts to explore the way."

Lu Ning smiled and replied.

"The old general doesn't have to worry, there will definitely be a battle for you in the future, wait here for the news of the scouts first, and then make sense."

At this time, Xu Da spoke.

"Wyvern, obey the general's command!"

Seeing Xu Da speak, Ma Feilong didn't dare to speak anymore and retreated.

Everyone was anxious, and they boarded the deck together, waiting for news, and waited until evening, when the breeze came slowly and the water was not rippling.

However, they had not yet seen the news from the scout ship, and everyone couldn't help but feel a little excited, and just wanted to go back to the cabin, when someone suddenly screamed.

"Look, what's floating on the surface of the sea."

Seeing more than 20 scattered foreign objects floating on the sea, Lu Ning immediately sent a small boat to check it.

After a while, the people on the small boat waved flags towards the big boat.

"It's our scouts, they've all had their throats cut and floated back with the sea breeze."

Soon, another small boat came over and retrieved all the corpses and put them in front of Lu Ning and some other soldiers.

The crowd was furious.

"Who did it?"

There was a corpse with a drifting bottle on it, and when I opened it, I found that it read: This is the territorial waters of the Heavenly King of Zhenhai, leave your fleet, and roll back to land by yourself.

Lu Ning hadn't heard of who the Zhenhai Heavenly King was, and after discussing with Zhu Di, he decided to meet this arrogant guy.