Not a textbook or a problem book

54

The first equation gives $x = \frac{c-b}{a}$, and the second gives $x = \frac{-c-b}{a}$. By direct verification we are convinced that the root satisfies the original equation (I, pp. 85-86).

The solution to inequalities is presented in the same formulaic manner. In those cases when the author tries to give some advice, only notifications are allowed.

Here, for example, is what recommendations for solving inequality look like:

$$\frac{(x+3)(x-2)}{x+3} > 0.$$

《When solving such inequalities, a mistake is often made by reducing the numerator and denominator by a common factor, in this case by $x+3$. This reduction is not finite, since the multiplier can take both positive and negative values. This inequality is equivalent to two systems of inequalities

$$\begin{cases} (x+3)(x-2) \ge 0, \\ x+3 > 0 \end{cases}$$

And

$$\begin{cases} (x+3)(x-2) \le 0, \\ x+3 < 0 \end{cases}$$

Since the theoretical matrix based on geometric ones is a simple collection of formulations of definitions and theorems taken from a school textbook. The appropriateness of such a “textbook summary” is not clear, especially since in a number of places the author’s presentation leaves much to be desired.

Some problems with geometric solutions are incorrect or uncertain (II, pp. 27, 53, 83, 93, etc.).

Afterwards they contain a whole series of questions that have long been excluded from the school curriculum and are not required in entrance exams (Horner’s scheme, Bezout’s theorem, extracting roots from complex numbers, the formula of a complex radik, a detailed theory of inverse trionometric functions). It is a pity that the author did not show the desire to display the material for the books particularly carefully, especially since these issues are not always presented in the best possible way.

For example, having long ago decided on the free evidence that the books in question represent an unguided accepted infinite greater value (I, p. 227); “if the model of the expression $2x+8$ is greater than 7, then this expression itself must be greater than 7 and less than -7” (I, p. 242); “let’s express cos 2x through a polyvine argument” (II, p. 215), etc.

It is said with all the evidence assessed that the books in question are not guided by an assumed infinite greater value (I, p. 227); “if the model of the expression $2x+8$ is greater than 7, then this expression itself must be greater than 7 and less than -7” (I, p. 242); “let’s express cos 2x through a polyvine argument” (II, p. 215), etc.

Not a textbook or a problem book

In 1970, the publishing house of the Leningrad branch of the Knowledge Society published the book by Ya. I. Maryanovsky “Knowledge for Youth. To help those entering the prison. “Physics” with a circulation of 215,500 copies. The book is based on “a somewhat shortened version of the author’s lectures, which he has been delivering for a number of years at the Central Lecture Hall to help those entering higher education institutions” *).

*) Here and below, quotes from the solution of the silent book are highlighted in quotation marks.

《The presentation is intended for a reader with secondary education》:

However, reader, do not rush to carefully study the manual. Considerable difficulties await you! Having tested the presented property for the reader: what should and should not be thought about weight?… If you, reader, look into this, they rightly refused to consider “Functions” $y = \text{Arc sin } x$ and others, but for some reason the author revives this outdated approach; his derivations of formulas between inverse trionometric functions and solutions of simple equations containing these functions are often incorrect due to the lack of necessary restrictions (II, pp. 244-257).

The books are replete with illiterate phrases for solving incorrectly or vaguely: “…the graph is a hyperbola with its vertex at the point…” (I, p. 208); “…the function… does not exist at these points, or, more precisely, takes on an infinitely greater value” (I, p. 227); “if the model of the expression $2x+8$ is greater than 7, then this expression itself must be greater than 7 and less than -7” (I, p. 242); “let’s express cos 2x through a polyvine argument” (II, p. 215), etc.

It is said with all the evidence assessed that the books in question represent an unguided accepted.infinitely greater value (I, p. 227); “if the model of the expression $2x+8$ is greater than 7, then this expression itself must be greater than 7 and less than -7” (I, p. 242); “let’s express cos 2x through a polyvine argument” (II, p. 215), etc.

Not a textbook or a problem book

In 1970, the publishing house of the Leningrad branch of the Knowledge Society published the book by Ya. I. Maryanovsky “Knowledge for Youth. To help those entering the prison. “Physics” with a circulation of 215,500 copies. The book is based on “a somewhat shortened version of the author’s lectures, which he has been delivering for a number of years at the Central Lecture Hall to help those entering higher education institutions” *).

*) Here and below, quotes from the solution of the silent book are highlighted in quotation marks.

《The presentation is intended for a reader with secondary education》:

However, reader, do not rush to carefully study the manual. Considerable difficulties await you! Having tested the presented property for the reader: what should and should not be thought about weight?… If you, reader, look into this, they rightly refused to consider “Functions” $y = \text{Arc sin } x$ and others, but for some reason the author revives this outdated approach; his derivations of formulas between inverse trionometric functions and solutions of simple equations containing these functions are often incorrect due to the lack of necessary restrictions (II, pp. 244-257).

The books are replete with illiterate phrases for solving incorrectly or vaguely: “…the graph is a hyperbola with its vertex at the point…” (I, p. 208); “…the function… does not exist at these points, or, more precisely, takes on an infinitely greater value” (I, p. 227); “if the model of the expression $2x+8$ is greater than 7, then this expression itself must be greater than 7 and less than -7” (I, p. 242); “let’s express cos 2x through a polyvine argument” (II, p. 215), etc.

It is said with all the evidence assessed that the books in question represent an unguided accepted.infinitely greater value (I, p. 227); “if the model of the expression $2x+8$ is greater than 7, then this expression itself must be greater than 7 and less than -7” (I, p. 242); “let’s express cos 2x through a polyvine argument” (II, p. 215), etc.

Not a textbook or a problem book

abatic expansion gas cooling…" (pp. 124-125).

So, the gas is in an isothermal cooling process. Let’s ask: what is the isothermal cooling process and how is it “strongly different” from the adnabatic one? Apparently, for many, the answer is not much.

If, reader, you haven’t figured out the proposed puzzles, then it’s too early for you to read the book. It needs to be simpler. In this case, the author “refers the reader to an elementary physics textbook edited by Academician G. S. Landsberg in three volumes” (p. 2).

Let us not, however, delude ourselves with the idea that everyone who failed the proposed test will listen to us. What advice can you give to such stubborn people?

To begin with, they must discard the outdated and distorted ideas about physical phenomena, definitions and laws that have taken root in them. Judge for yourself.

It was previously believed that the potential energy of bodies increases with increasing altitude. But according to Maryanovsky, this is true only “at first glance” and only for “heights much less than the radius of the Earth” (pp. 77-78).

What should be expected from a body experiencing two unequal forces in the horizontal direction? Faster movement? We made a mistake. “For example, the box is on the floor. We applied force to it, but the box does not move. Our force is less than the force of resting friction.” (page 23). (Let us clarify that this does not mean the maximum value of the static friction force.)

What is customary to do if, when calculating the resistance of a section, reverse the problem and solve the problem again” (p. 175).

Skeptics will say that the direction of the point does not affect the sign of the resistance, that the current could already be given and its direction can be changed only by changing the polarity of all batteries included in the target. Oh, those skeltics. Stay away from them, reader! Their skelticism comes from insignificance and the desire to hide it. Ask this: what is the minimum value of a vector (not the module, but the vector itself)? We bet the skeltic will say he doesn’t know such a value doesn’t exist. And our reader knows (if it is already added to page 17). But enough about the skeltics. Let them study. And almost (so time) even such “most important” concepts as “field energy at a point” (p. 148), or “everything pushing out the force of the electrostatic field” (problem 82), the introduction of which we are entirely obliged to this book.

Now that we’re talking about problems, let’s look at a few more. For example, problem No. 48. A body rotates with a strand (not a rod!) in a vertical plane with a constant linear speed. And since the constancy of speed contradicts the law of conservation of energy (this law! It gets in the way all the time!), the author does this: he abolishes the law in silence, formulates the condition of the problem, and brings it back to life in the solution.

Equally fantastic resistance events of the circuit section “the answer is negative”?

“In this case, you need to reverse the direction of the point and solve the problem again” (p. 175).

Skeptics will say that the direction of the point does not affect the sign of the resistance, that the current could already be found or set and its direction can be changed only by changing the polarity of all batteries included in the target. Oh, those skeltics. Stay away from them, reader! Their skelticism comes from insignificance and the desire to hide it. Ask this: what is the minimum value of a vector (not the module, but the vector itself)? We bet the skeltic will say he doesn’t know such a value doesn’t exist. And our reader knows (if it is already added to page 17). But enough about the skeltics. Let them study. And almost (so time) even such “most important” concepts as “field energy at a point” (p. 148), or “everything pushing out the force of the electrostatic field” (problem 82), the introduction of which we are entirely obliged to this book.

Now that we’re talking about problems, let’s look at a few more. For example, a problem contradicts the law of conservation of energy (this law! It always gets in the way!), the author does this: silently repeals the law, formulates the condition of the problem, and brings it back to life in the solution.

But enough about physics. Teachers may get the wrong idea about the manual as a purely special and one-sided book. We dare to dissuade him. Food for thought is also offered to mathematicians (pp. 7, 25, 127, 129, 139, etc.) and logicians. It should be noted that from the point of view of the Russian language, not all is well in the book. “…A relational approach relative to the system” (p. 3). “A solid (if it is not solid)” (p. 121). “The work done by a force is a measure of the energy accumulated in its process” (p. 77).

And one stylistic device of the author will be interesting to both lyricists and physicists at the same time. It’s about the brackets used.

“Syles of gravity (gravitational)” (p. 55). “Gravitational forces (forces of gravity)” (p. 61).

Finally, check yourself to read your new physical effects. Two equal one-phenic charges are given. Where should the third charge of the same sign be placed so that it remains in equilibrium? Obviously, in the middle of the segment connecting these charges. So, if the author’s argument used in this situation (task No. 81): “The position we found is the only one in which the charges are in equilibrium. Therefore, the charge equilibrium is stable - it seems. You will be convinced that the very fact of the stability of the balance is beyond doubt, the author will achieve his goal. And for us, we can only wish those from the great army of 215,500 happy owners of this book who are inclined to uncritically assimilate the material and also have a sense of morality: may you never meet an examiner who did not have time to study the “Manual” and remained with traditional views (yes, you can meet also!). Always with him can lead to disastrous results. Do not forget that “this book is not a textbook or an assignment” (p. 2). And this is the only quote of all those given that does not need comment.

S. V. Atsezulov,
V. A. Baryshev