Daniel Bernoulli (1700 – 1782) derived the famous fluid equation named

Dear spetznaz,

My friend, I'm happy to respond.

Actually, comma + "giving" is perfectly correct. In fact, I would say that version (D) is 100% grammatically correct, but it is a rhetorical nightmare. Here's version (D):
(D) Daniel Bernoulli (1700 – 1782) derived the famous fluid equation named for him, giving an explanation of the generation of the lift of an airplane’s wing, and made a discovery that led to an early method of measuring blood pressure.

Notice that version (D) is the longest of the five answer choices: that doesn't automatically mean an answer is wrong, but it's always a red flag that deserves our attention. Notice that version (D) is packed with nouns, nouns that are action words ("explanation," "generation"). As a general rule, a sentence is more compact and direct when the action words are in verb form. Putting action words in noun form is a way to make a choice sound bloated, weak, and indirect. For example, why on earth would we say "giving an explanation" rather than simply "explaining"? Even one action-word-as-noun is problematic, but this choice has two in a row! Holy mackerel! Choice (D) seems as if it is trying to win a contest to be the most rambling, verbose, and mealy-mouthed of the five answer choices. Yes, it's 100% grammatically correct, but rhetorically it's such a disaster that it should be taken out back and shot!

Remember that the GMAT SC is NOT purely a test a grammar. Instead, on the GMAT SC, grammar and logic and rhetoric are three equally important strands, and a student can't afford to ignore any of these.

Does all this make sense?
Mike

im still unable to understand why A is incorrect. Firstly, isnt it unidiomatic to say 'named for him'? Secondly, DB deriving a formula to explain the generation of lift seems logical to me as a lay man without physics or history background. So the only reason to eliminate A according to me would be the concentrated adjectives in 'airplane's wing's generation of lift', which seems awkward.

Any correction or clarity on the above would be appreciated.

Dear OreoShake,

I'm happy to respond.

Think about this structure
{person] did X to do Y
That structure is the infinitive of purpose. It implies intentionality. It implies that the person, in undertaking action X, had the explicit purpose of accomplishing Y.

Consider the sentences:
1) Washington crossed the Delaware to stage a surprise attack on the Hessians.
This first is logical and historically accurate. That's precisely what Washington was trying to do that night.
2) Washington crossed the Delaware to look heroic in a painting.
This one is patently absurd. Yes, one of the many consequences of Washington's action is that, much later, he cut a particularly heroic figure in a painting. Nevertheless, phrasing this with an infinitive of purpose is absurd, because the very last thing on Washington's mind on that stressful evening was how some artist would paint it more than half a century later.

Now, if you think that's absurd, consider (A) from this problem.
Daniel Bernoulli (1700 – 1782) derived the famous fluid equation named after him, to explain an airplane’s wing’s generation of lift, and made a discovery that led to an early method of measuring blood pressure.
Yes, the structure "an airplane’s wing’s generation of lift" is less than ideal and probably would not be part of a correct answer, although it's hard to say whether this alone would disqualify an answer choice. The BIG problem with (A) is the absurd implication of intentionality. You don't have to have advanced technical knowledge about the history of science, but you have to have the basic idea that in the eighteenth century, there were no airplanes. To say that Bernoulli was trying to explain something about airplanes, that one of his explicit intentions in deriving the equation was to explain airplanes, is absurd, because the airplane didn't come into existence until more than a century after his death. There is no way he could have know anything about airplanes, so there is no way he could be trying to explain anything about them. That's the big problem with (A).

Remember, on the GMAT SC, an effective sentence is one in which grammar and logic and rhetoric all work together to produce meaning.

Does this make sense?
Mike

The story of this sentence is about a man named DB, who derived an equation and made a discovery that led to something.

A - Nothing wrong grammatically although the mammoth that are possessive's in this sentence could be avoided. Keep for NOW.
B - 'and this' creates a separate clause, and it's followed by another clause which breaks the entire flow of the sentence. It's better to use a modifier here, to explain what the equation does. OUT.
C - Clearly OUT. I laughed when I read this sentence. He derived an equation, then NAMED it after himself, then explained a phenomena, and finally made a discovery. Fake Parallelism that clearly destroy's the meaning of the sentence. OUT.
D - Extremely verbose. Giving an explanation is redundant. We could just say explains. OUT.
E - Nothing wrong grammatically. KEEP.

Now it's down to A & E.
The comparison is between intention Vs. explanation, so do we need an adverbial phrase to show intent, or a noun-modifier to explain what the equation does.
I chose E because it was more succinct, and later I did realise that airplanes did not exist back in 1700s so there could be no intent on DB's part to explain a wing's lift.

mikemcgarry
My question is with regards to the phrase, "to explain....." in option A. Is that an adverbial modifier?

Dear akshayk,

I'm happy to respond.

My friend, did you see in the post immediate before yours that I explained that this was an infinitive of purpose. Yes, the infinitive of purpose is one kind of verb modifier, one kind of adverbial modifier. Because it makes clear the purpose of an action, it is always modifying a verb.

It's obvious that you are quite intelligent and have great potential. Before you ask a question on a thread, it's always good to check to what extent that issue already has been discussed. This sort of thoroughness is one of the aspects of asking an excellent question, and of course, that's one of the habits of excellence. Remember: how you do anything is how you do everything.

Does all this make sense?
Mike

Hi Mike,
Actually i chose option A, as i didnt know "named for him" is a correct idiom.
Also , "equation named after him, to explain an airplane’s wing’s generation of lift", is n't an example of using inifinity of purpose?, did bernoulli derive the equation to explain the lift. Please help me eliminate option A.

Dear hellosanthosh2k2,

i"m happy to respond.

First of all, "named for him" and "named after him" are both 100% correct idioms. You may find helpful these free GMAT Idiom Flashcards.

Yes, the phrase "to explain an airplane’s wing’s generation of lift" is an infinitive of purpose. It's also a gorgeously awkward phrase--it's hard for two possessives in a row not to be astonishingly awkward. That's problem #1 with (A), a rhetorical problem. Then problem #2 is the logical problem. The infinitive of purpose implies that the actor had conscious intention to so something. Well, the question very conveniently gives Mr. Bernoulli's dates, in the 18th century. You don't need to have a detailed knowledge of history, but you need to have the gist that there were no airplanes in the eighteen century--airplanes didn't come along to the 20th century, so someone two centuries earlier would have had no knowledge of them and therefore could form no purposes regarding them. Thus, the infinitive of purpose is illogical in (A).

Does all this make sense?
Mike

mikemcgarry,
why "which" does not refer to fluid?

Dear chesstitans,

I'm happy to respond.

In the construction "fluid equation," we have a pair of nouns in which one is essentially modifying the other. Even though "fluid" is a noun, in a way it is acting like an adjective here. It's subordinate to the second noun, "equation." Because the second noun has rhetorical priority, no modifier would ever pass over it to refer to the first noun.

Rhetorical priority is an underestimated dimension of pronoun-antecedent agreement.

Does all this make sense?
Mike

Okay there a few different things to consider here. I can tell that C is wrong because there is inappropriate parallelism. A is awkward sounding. ‘airplane’s wing’s generation of lift’ sounds strange. In D ‘giving an explanation…’ is modifying ‘named after him, I am pretty sure that it is not correct. Between E and B, E sounds more natural, since B has two ands. I am going to say E is correct.

Is "named for him" a correct idiom?

Sorry I don't get it. How "named for him" is correct. It has to be "named after him" isn't it ? Or we choose E just because rest are more wrong?

Both name X after Y and name X for Y are correct.

I don't agree with Mike's argument that "named for him" is a vital modifier. I have solved many official GMAT questions with "vital modifier" and "which" construction, and in all those questions the modifier held information that added value. In the case above, modifier "named for him" adds no such value.

Hi AKSU2020,

But don't you think that we need the named for him bit in order to recognize which "famous fluid equation" the sentence refers to?

Hi Ajitesh,

Thanks for your reply!

I think that the use of "the famous equation" and "discovery" made me think more about what the equation does than who it is named for.

Regards

Hello mikemcgarry


Thank you for your great problem and your explanation!

However, I still have a question about the correct answer choice E: doesn't it change the original meaning?

The original version is "explain an airplane’s wing’s generation of lift" --> it could be: explain what it is, how it is done, why it needs to be done, when it is done, how significant it is, and so on.

But in E, "explains how an airplane’s wing generates lift" changes the meaning to: explain how it is done.

Could you please explain this as I got really confused. Thank you so much!