Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

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bob bundy
2013-06-12 18:54:51

hi debjit625

Ok, thanks.  So they're saying 45.58... is approximately 45 degrees.  If they're going to choose to give the answer to the nearest degree then it should be 46.

But the important thing is you know what you're doing even if they don't.

General point about rounding: Do the calculation with as much accuracy as you can throughout.  Then think what is  a reasonable amount of rounding and do it at the end., not during the calculation.

example of what can go wrong.

15 * √24

√24 = 4.898...  round off too soon ---> 5

15 * 5 = 75

Correct value is 73.4846922834953..... so if you round that off to the nearest integer you get 73.

Bob

debjit625
2013-06-12 17:53:59

Yes stefy I agree with you,  but still we use approx symbol for that... don't we ?,in the book they directly used equal symbol.

Bob the topic was about... calculating vectors...
Their are two force vectors given,first one 70N north and another is 50N south west,so calculate the resulting force and direction.

bob bundy
2013-06-12 03:25:47

hi debjit625

What was the topic?  That will help in deciding what rounding is acceptable.  The cosmological constant for example

Bob

anonimnystefy
2013-06-12 03:04:34

Well, you rounded the answer too, but it is correct. That expression is approximately 1.02.

debjit625
2013-06-12 03:02:17

Well,I thought that but in that case physics books use

approx symbol in general.

So I am right with the math ?

anonimnystefy
2013-06-12 02:53:06

Well, physics books tend to round their answers very much. I think it is acceptable to do so.

debjit625
2013-06-12 01:59:09

Hi,
In a physic book I found this

Is the math correct ? as far my math goes it should be 1.02

Thanks