Split - Simplify - Need to follow PEMDAS

Jomo said:
SO

SOHCAHTOA gives the definition of some trig functions very nicely. It is not a procedure as with PEMDAS!

SOHCAHTOA ==> S=O/H C=A/H and T=O/A
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It is not?

I have seen it being used to calculate sin(theta) in a 3:4:5 triangle - with a sketch.

sin(t) = 3/5 or 4/5 (depending on the location of 't')

Excellent procedure...
 
Subhotosh Khan said:
It is not?

I have seen it being used to calculate sin(theta) in a 3:4:5 triangle - with a sketch.

sin(t) = 3/5 or 4/5 (depending on the location of 't')

Excellent procedure...
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Nonsense! You used the definition of sine to get your answer. If I am wrong then give me the steps for this procedure.
 
Jomo said:
Nonsense! You used the definition of sine to get your answer. If I am wrong then give me the steps for this procedure.
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Sin(t) = O/H = 3/5

And people remember definition of sine with that acronym - and calculate (procedure) with that acronym (without calculator).
 
Subhotosh Khan said:
Sin(t) = O/H = 3/5

And people remember definition of sine with that acronym - and calculate (procedure) with that acronym (without calculator).
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I already said (and showed) that SOHCAHTOA gives the definition of three trig functions. I would advise ALL trig students to know this acronym.
 
I watched the video referenced in post # 17. The video shows problems still worked
out by PEMDAS, just that it emphasizes separating the parts to be exponentiated, multiplied, and/or divided first into boxes (rectangles) before they are later added and/or subtracted, as the case may be.

And, Jomo, students will still make errors with this amended technique, aside from
addition and subtraction mistakes, because they will have to deal will expressions
such as \(\displaystyle \ 100 \div 10 \div 2, \ \ \) for example, as shown in an example
as part of a larger order of operations problem.
 
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Jomo said:
What you are saying is exactly correct, PEMDAS works fine all the time. Some students however do not use it correctly. That is the problem. Just because it works does not mean it is a good method to teach, that is my point. The fact that the world uses PEMDAS does not mean anything to me at all.
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It isn't the students using it wrong that I have a problem with. The students are simply learning it and make mistakes. But the number of educators out there, High School or college level, that use it wrong is terrible. Physics (and probably Engineering) professors do it all the time and I would love to go back in time and "hit them a kick" as my Grandmother used to say.

-Dan
 
topsquark said:
It isn't the students using it wrong that I have a problem with. The students are simply learning it and make mistakes. But the number of educators out there, High School or college level, that use it wrong is terrible. Physics (and probably Engineering) professors do it all the time and I would love to go back in time and "hit them a kick" as my Grandmother used to say.

-Dan
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No ... not engineering!

We Engineers don't make mistakes

Only commit BLUNDERS.​
 
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