Nikolai Kondratieff concluded in the 1920s that since the 1780s, Western econ- omies have generally followed a cycle of how many years?

54

Explanation:

Nikolai Kondratiev was a Soviet Union economist. He was popular for his economic cycle theory called Kondratieff Wave. This economic wave is defined as the intervals of evolution believed to correct itself. This cycle is caused due to technological invention that leads to an extended time of wealth.

According to him, this period started during the steam engine invention, from the 1780s to the 1830s. He concluded that Western economies have generally followed a cycle of forty to sixty years or to be specific fifty four years exactly.

explanation: we can only guess at how our actions may be perceived in the future. doing something really big like killing lots of people, saving lots of people, affecting the lives of lots of people is a sure fire way of being remembered in historical records. we can also make a difference in the history records by being a small influence on something bigger, whether that is as a civil servant, scientist or artist.

of course you could argue that we all affect history just as tiny cogs in a   bigger machine.

if you mean how do people influence our opinions of things which have already happened, then simply by writing a book which looks at things form a different perspective and trying to convince people that this perspective is more accurate or truthful. people do it all the time i.e. richard the third was a terrible or was he? plenty would disagree, it's just that their views aren't the most widely known.n:

richard milhous nixon (january 9, 1913 – april 22, 1994) was the 37th president of the united states, serving from 1969 to 1974, when he became the only president to resign (quit). he is also known for corruption and the watergate scandal which resulted in the public losing trust in him and his resignation.