can u solve this?

[kishanji]

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find all the values of x at which the

f(x)=(x^2-1)/(x^3-x^2-2) is discontinuous?

i think there is something wrong with the question !

 

[ForcedEntry]

-1 and 2

 

[lfc-2086]

set the denominator = 0 and solve.......not sure how to solve it tho.....sorry.
i.e. find the vertical asymptote...according to a graphing calc shud b about 1.69.....any one know a short cut to solving cubic equations.....wish we could use our calculators 🙂

 

[ForcedEntry]

oooopps...I didn't even see the demon as a cubic (DOH!)

 

[lfc-2086]

i guess i would just backsolve from the given answers n see which one gives me 0.....

 

[kishanji]

the given answer is 0, 1, -2 which i think is totally bias. and there is no way to solve that cubic denominator .. not atleast by any known method.

 

[Lasche]

f(x)=(x^2-1)/(x^3-x^2-2) is discontinuous?

can you just factor out the x from the den and set it = to 0?

x(x2-x)-2 = 0
then x-2 =0 and (x2-x )= 0
x = 2 and x2 = x , x must be a 0 or 1

 

[infinitiiz]

x^3 - x^2 - 2 = 0 to get discontinued line

0, -1, -2 .. all wrong ..
Simply plot in the numbers and u won't get 0

There is a chapter in the calculus textbook just to solving these kind of problems. Something like Ax + Bx +Cx etc.

 

[unit18]

The answer is

1.6956207695598597

This is a tough one. I will admit solving cubic equations is probably non going to be on the PCAT. I wouldnt worry about it.

 

[lfc-2086]

phew.....i was about to go nuts....just one of those people who have to answer the damn question....or it bugs me for the rest of my day....hope i won't do that on the pcat tho...😀

Lasche: if i remember rite you can't solve it ur way;u can only factor if
Ax+Bx+Cx+Dx.....=0 in this case it would equal 2.....but if there are an even number of terms u can factor a common term in each n then set each equal to zero....kinda like a quadratic......

 

[infinitiiz]

yeah .. graphic calculator would give the same answer as Unit18 .. though, to solve it manually, gotta flip to that chapter I was talking about

 

[lfc-2086]

hey infinitiiz......do u have a short cut to solving the cubic eqs. .....please let us know.....after all sharing is caring 👍 ......thanks

 

[kishanji]

there is no way to solve the denominator. the person trying to teach you about solving this kind of denominator is just making some non-mathematical "blunders". I was concerned bcz this was the first problem of the practice exam and i took 5 minutes trying to solve this and was not able to solve the last 2 problems within time period.