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Question using the trapezoidal rule (1 Viewer)

kloudsurfer

Member
Joined
Jun 6, 2006
Messages
848
Location
Narellan
Gender
Female
HSC
2007
Hey,

Im stuck on this question. I know how to do it, but I keep getting the answer wrong and I dont know why. Im sure I made an error somewhere but I cant seem to pick it up and its driving me crazy!

Heres the question: (i dunno how to write all the symbols on the computer)

"Use the trapezoidal rule to find an approximation for

b=5, a=1 (i cant draw the squiggly thingy), 1/x^2 dx using 4 subintervals"


After subing everything into the formula, I got:

= 1/2 [(1+0.04) + 2 (0.64 + 0.16 +0.071111...)]
= 1.39 (2dp)

But the answer is 0.94.

Im sure I have just made a silly mistake, so if anyone would be able to help it will be appreciated.

Thanks
 

jyu

Member
Joined
Nov 14, 2005
Messages
622
Gender
Male
HSC
2006
kloudsurfer said:
Hey,

Im stuck on this question. I know how to do it, but I keep getting the answer wrong and I dont know why. Im sure I made an error somewhere but I cant seem to pick it up and its driving me crazy!

Heres the question: (i dunno how to write all the symbols on the computer)

"Use the trapezoidal rule to find an approximation for

b=5, a=1 (i cant draw the squiggly thingy), 1/x^2 dx using 4 subintervals"

After subing everything into the formula, I got:

= 1/2 [(1+0.04) + 2 (0.64 + 0.16 +0.071111...)]
= 1.39 (2dp)

But the answer is 0.94.

Im sure I have just made a silly mistake, so if anyone would be able to help it will be appreciated.

Thanks
Wrong substitutions

1/2 [(1+0.04) + 2 (1/4 + 1/9 + 1/16)]

:) :) :wave:
 

kloudsurfer

Member
Joined
Jun 6, 2006
Messages
848
Location
Narellan
Gender
Female
HSC
2007
jyu said:
Wrong substitutions

1/2 [(1+0.04) + 2 (1/4 + 1/9 + 1/16)]

:) :) :wave:
Ahhhh! Thanks!!!!

I corrected an earlier mistake and forgot to change something else

Thankyou!!!!!!
 

bos1234

Member
Joined
Oct 9, 2006
Messages
490
Gender
Male
HSC
2007
hello

If u wanna write the symbols, go to microsoft word
Insert > Object > equation (or equation editor)

It takes a bit of time getting used to

goodluck and goodnight
 

kloudsurfer

Member
Joined
Jun 6, 2006
Messages
848
Location
Narellan
Gender
Female
HSC
2007
bos1234 said:
hello

If u wanna write the symbols, go to microsoft word
Insert > Object > equation (or equation editor)

It takes a bit of time getting used to

goodluck and goodnight
Mine doesnt have equation or equation editor :(
 

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