function e5q8 *
- Thread starter tamiatha
- Start date
Re: function: if f(x) = 5x^2-4/x, find 4 (my answer: 99)
You need to clarify the problem for us. Which of these is the correct problem?
f(x) = (5x[sup:1th84bix]2[/sup:1th84bix] - 4) / x
OR
f(x) = 5x[sup:1th84bix]2[/sup:1th84bix] - (4/x)
It DOES make a difference!!
That said, the value of 5x[sup:1th84bix]2[/sup:1th84bix] when x = 4 is 5(4)[sup:1th84bix]2[/sup:1th84bix].....and that is NOT 400. You need to follow the order of operations. In evaluating 5(4)[sup:1th84bix]2[/sup:1th84bix], you must do the exponent FIRST, and then the multiplication.
tamiatha said:
You need to clarify the problem for us. Which of these is the correct problem?
f(x) = (5x[sup:1th84bix]2[/sup:1th84bix] - 4) / x
OR
f(x) = 5x[sup:1th84bix]2[/sup:1th84bix] - (4/x)
It DOES make a difference!!
That said, the value of 5x[sup:1th84bix]2[/sup:1th84bix] when x = 4 is 5(4)[sup:1th84bix]2[/sup:1th84bix].....and that is NOT 400. You need to follow the order of operations. In evaluating 5(4)[sup:1th84bix]2[/sup:1th84bix], you must do the exponent FIRST, and then the multiplication.
D
Deleted member 4993
Guest
Re: function e5q8
If your problem look like:
\(\displaystyle f(x) \, = \, \frac{5x^2-4}{x}\)
in that case you should write it as:
f(x) = (5x^2 -4)/x
_________________________________
what you wrote -- f(x) = 5x^2-4 / x --- translates to (using PEMDAS):
\(\displaystyle f(x) \, = \, 5x^2 - \, \frac{4}{x}\)
Which one of the above correctly represent your problem?
tamiatha said:
If your problem look like:
\(\displaystyle f(x) \, = \, \frac{5x^2-4}{x}\)
in that case you should write it as:
f(x) = (5x^2 -4)/x
_________________________________
what you wrote -- f(x) = 5x^2-4 / x --- translates to (using PEMDAS):
\(\displaystyle f(x) \, = \, 5x^2 - \, \frac{4}{x}\)
Which one of the above correctly represent your problem?
D
Deleted member 4993
Guest
Re: function e5q8 w
Tamiatha,
Aladdin has provided you with correct solution.
However, I strongly suggest that you understand - how is that different from the solution that you had provided and why was your solution incorrect. You did not follow principle of PEMDAS. That was also your trouble while posting - you did not use proper grouping symbols (brackets) - to indicate proper order of operations. You thought you posted the problem correctly - but in fact you had posted different problem, than you had meant to post.
You need to really get totally familiar with these routine operations - otherwise it will be very difficult as you try to proceed. the website "purplemath" gives you lot of worked out examples. Go through "every" problem and be confident that you can do those. These routine problems are very important - need to have those down-pat.
Good luck....
Tamiatha,
Aladdin has provided you with correct solution.
However, I strongly suggest that you understand - how is that different from the solution that you had provided and why was your solution incorrect. You did not follow principle of PEMDAS. That was also your trouble while posting - you did not use proper grouping symbols (brackets) - to indicate proper order of operations. You thought you posted the problem correctly - but in fact you had posted different problem, than you had meant to post.
You need to really get totally familiar with these routine operations - otherwise it will be very difficult as you try to proceed. the website "purplemath" gives you lot of worked out examples. Go through "every" problem and be confident that you can do those. These routine problems are very important - need to have those down-pat.
Good luck....