The Appearance of a God-Tier Question

The grade director began to state the problem:

"If △ABC is an obtuse triangle, find the range of values for arccos(sinA) + arccos(sinB) + arccos(sinC)."

As the director spoke, various reactions rippled through the students below.

Most students, including the academic underachievers and the mediocre, were left dazed, not even understanding what "arc" meant. In the high school curriculum, "arc" was not a core topic; it was elementary material, mentioned only briefly in a corner at the bottom of a page in some math textbook. Since most students hadn't mastered the basics, they naturally didn't know what "arc" signified, recognizing the term at best as something vaguely familiar.

Many began to whisper among themselves:

"Holy crap, I don't even understand the question!"

"Math is truly a subject that can drive a person insane!"

"I bet there are ten thousand grass-mud horses galloping through Chen Zhao's mind right now..."

"You can't even understand the question, let alone solve it? You'd have better luck dreaming!"

"The director is clearly trying to slap Chen Zhao in the face with a hard problem! You think you know everything? Here's something you don't know!"

"Chen Zhao is acting crazy today, insisting on bragging. Now he's stuck. He could have just stood at the back of the classroom for the morning, but he had to go and get himself a week-long suspension."

"If Chen Zhao can solve this, I'll eat the test paper on the spot!"

While the underachievers and mediocre students gossiped, the top students sitting in the front row—such as the class rank one Chen Miaoran, rank two Zhang Shucheng, and rank three Liu Chang—had already picked up their pens, scribbling furiously on their scratch paper, alert and focused as they attempted to solve the problem.

The reason top students are top students is because they possess a wolf-like hunger for problems; they want to solve every new question they see, and if they can't, they feel miserable! A true top student walking down the street who suddenly spots two things on the ground—a crisp hundred-yuan bill and a page torn from a problem set—would definitely choose to pick up the problem first, not the money!

Solving problems brings me joy! Scores are life!

But this time, after scribbling for a few moments, the top students suddenly hit a wall. Instead of joy, their faces were filled with frustration.

The problem seemed simple enough, just a single line asking for a range of values. But when they actually tried to solve it, they found they didn't know where to start!

It felt like there were too many things to consider, or perhaps they were overthinking it. None of the conventional methods worked. Trying to brute-force it left them clueless as to where to begin. It was like a tiger biting a hedgehog—there was no place to sink their teeth in!

Now, only one method remained: judging by the options. Many multiple-choice questions are hard to solve directly, but looking at the options can provide clues. The top students looked up toward the blackboard.

Chen Zhao had already finished writing the problem on the board.

This was a multiple-choice question. Just as the director was about to read out the four options, Chen Zhao's hand didn't stop; he moved to the next line and wrote down the answer directly—

(90°-270°)

After writing it, Chen Zhao turned to look at the director, "The answer is ninety degrees to two hundred and seventy degrees, right, teacher?"

The whole class erupted!

He'd only just finished copying the question, and the answer was already out?!

The students were stunned. This was way too fast, wasn't it!?

Even if you used an app like Xiaoyuan Sou Ti or Zuoyebang, you'd still need time to take a photo and upload it. You just gave the answer straight away?

In the front row, the top students were even more horrified. The layman watches the spectacle, while the expert watches the technique. The underachievers couldn't solve the problem anyway, so they didn't realize how difficult it was; they just thought Chen Zhao was fast. But the top students were different; they understood the problem, which is exactly why they knew how incredibly difficult it was to solve!

The class rank three, Liu Chang, nudged the rank two, Zhang Shucheng, with his elbow, "Did he get it right?"

Zhang Shucheng looked blank: "I don't know how to solve it!"

Zhang Shucheng then poked the class rank one, Chen Miaoran, with his pen and whispered, "Is the result Chen Zhao calculated correct?"

To his surprise, Chen Miaoran also looked bewildered, "This problem... I haven't solved it yet, I have no idea where to start."

The surrounding students overheard the top students' conversation and were dumbfounded. Even the top three in the class couldn't do it? Just how hard was this problem?

Yet, for such a difficult problem, Chen Zhao gave the answer the moment he finished copying it?

What the hell!

Could it be... that he just guessed?

This thought popped into some students' minds, and the more they thought about it, the more it made sense. There was no way Chen Zhao could solve such a hard problem. Besides, this was a question from ten years ago, ancient history that wasn't even cited in study guides, so it was impossible for him to have memorized the answer. There was only one explanation: Chen Zhao was just spouting nonsense!

But the director's expression changed abruptly!

"Hmm... that's correct, that is the answer." The director nodded.

In an instant, the class fell into a deathly silence!

The entire classroom was deathly quiet!

He actually... got it right?

All the students were bewildered. What on earth was going on? Did the director collude with Chen Zhao to put on a show? That was impossible! Or did someone prompt Chen Zhao from below? That didn't make sense either; the top three in the class hadn't solved it! Who could have prompted him?

Chen Zhao ignored the class's reaction and simply looked at the director, "Then please give me the second question, teacher!"

The director nodded, his expression becoming complex. He probably hadn't expected Chen Zhao to solve this problem by mental calculation alone, without even using the blackboard for scratch work, and arriving at the result immediately. It was as if this multiple-choice question, the hardest from a math exam ten years ago, was as simple as one plus one equals two to him!

After a moment of thought, the director spoke:

"The next question is the final fill-in-the-blank from the joint exam of 100 schools across 4 provinces five years ago. Please listen to the question."

The pupils of every student in the class constricted at the same time: the Four-Province Hundred-School Joint Examination!

A month ago, everyone had just participated in this Four-Province Hundred-School Joint Examination. The scope of this exam, as the name suggests, involved students from one hundred schools across four provinces taking the exact same test paper. This paper was compiled by gold-medal teachers and senior professors from the education sector across the four provinces; the difficulty was extreme, the question types were highly innovative, and the volume of questions was immense! In short, it was a devilish exam paper!

Just how hard were the questions on the Four-Province Hundred-School Joint Examination?

To put it this way, some students who could score five hundred points on their regular school midterms and finals would score less than four hundred on this joint exam!

Now, the director was going to pull out the most difficult fill-in-the-blank question from that very exam!

This was meant to kill Chen Zhao!

The director suddenly picked up a piece of chalk and a ruler from the podium to the side and began to draw on the blackboard himself.

Clearly, this was a problem that required solving through geometry!

Amidst the rhythmic clatter of chalk, a geometric figure so strange it made one dizzy appeared! It consisted of three cylinders, with two lying on top of one, and a cross-section cutting through all three from the top-left to the bottom-right, revealing an irregular surface!

"Find the function for this line and this line," the director said, drawing two bold lines over the image.

The entire class was stunned!

A god-tier problem!

If you can't find the book by its title, you can try searching for the author; perhaps the name has simply been changed!

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