Post by: MrsStark on January 29, 2015, 05:26:09 pm
x/(a-b) + 2x/(a+b) = 1/ (a^2 - b^2)
If you can help me, thanks so much!
Post by: MrsStark on January 29, 2015, 05:27:32 pm
Post by: brightsky on January 29, 2015, 05:29:19 pm
Compare the two fractions, and you will see that
Post by: MrsStark on January 29, 2015, 05:49:07 pm
Compare the two fractions, and you will see that.
Thank you :)
Post by: MrsStark on February 01, 2015, 12:08:44 pm
p^2(1-x) - 2pqx= q^2(1+x)
solve for x:
(p-qx)/t + p = (qx-t)/p
Post by: Hutchoo on February 01, 2015, 01:03:48 pm
solve for x:
p^2(1-x) - 2pqx= q^2(1+x)
solve for x:
(p-qx)/t + p = (qx-t)/p
I tend to find these questions annoying because they're so easy to screw up! It's just a bunch of messy algebra. I suggest you try the first one yourself, but I will do the second one for you.
Solve for x:
Now expand:
Multiply both sides by
Collate like terms:
Simplify and solve:
Hopefully I didn't make any silly algebra mistakes.
Post by: MrsStark on February 01, 2015, 09:36:48 pm
I tend to find these questions annoying because they're so easy to screw up! It's just a bunch of messy algebra. I suggest you try the first one yourself, but I will do the second one for you.
Solve for x:
Now expand:
Multiply both sides by:
Collate like terms:
Simplify and solve:
Hopefully I didn't make any silly algebra mistakes.
Yeah I hate these qs too lol its simple but easy to mess up I know !!
Yup, I tried the first one again and I got it yay!
Thanks for helping! and no I don't think you made any mistakes :)
Post by: Hutchoo on February 01, 2015, 10:22:57 pm
Post by: MrsStark on March 10, 2015, 10:03:43 pm
The cost of a taxi trip in a particular city is $4 up to and including 2km. After 2km the passenger pays an additional $2 per km. find the function f which describes this method of payment and sketch the graph of y= f(x), where x is the number of km travelled ( use a continuous model)
okay so you don't have to draw the graph for me but I have trouble with worded questions and don't get how the function is derived
Post by: keltingmeith on March 10, 2015, 10:13:45 pm
Revising for my functions sac and stumbled on this question!
The cost of a taxi trip in a particular city is $4 up to and including 2km. After 2km the passenger pays an additional $2 per km. find the function f which describes this method of payment and sketch the graph of y= f(x), where x is the number of km travelled ( use a continuous model)
okay so you don't have to draw the graph for me but I have trouble with worded questions and don't get how the function is derived
Let x=number of kilometres travelled, then f(x) describes how much the person owes per kilometre.
For the first 2km, f(x)=4 (hopefully easy to see). After that, f(x) will raise $2 per kilometre, so it will be f(x)=2x+4 - BUT, we must remember to take off the 2 kilometres already travelled, giving us f(x)=2(x-2)+4=2x-4+4=2x
So, we get:
f(x)=4, 0<=x<2
f(x)=2x, x>=2
You should write this as a proper hybrid function.
Post by: MrsStark on March 15, 2015, 07:02:18 pm
Post by: keltingmeith on March 15, 2015, 07:08:53 pm
How do you find the inverse of a 3 x 3 matrix using the cas? it doesn't really show it in my textbook..
Just put it to the power of -1.
Post by: MrsStark on March 15, 2015, 07:13:09 pm
Just put it to the power of -1.
yeah I have been but I get a strange answer :s according to the back of the book answers its wrong.. don't know whats up with that..
Post by: keltingmeith on March 15, 2015, 07:17:26 pm
Post by: MrsStark on March 15, 2015, 07:28:41 pm
Put the matrix here, I'll tell you what the inverse should be and we'll compare to the book. Book could be wrong.
figured it out, my book is secondhand and its been written on and rubbed with rubber and I just misread a number -.- oh dear. I got the answer its all good, thank you for wanting to help :)
Post by: MrsStark on March 31, 2015, 11:09:18 am
2^(x) X 3^(x+1)= 10
Post by: wobblywobbly on March 31, 2015, 06:38:29 pm
hey can someone please help me solve for x?
2^(x) X 3^(x+1)= 10
2^x X 3^x X 3 = 10 (splitting up 3^x+1)
2^x X 3^x = 10/3
(2 X 3)^x = 10/3 (Power rule: (ab)^n = a^n x b^n)
therefore, log6(10/3) = x
Post by: Callum@1373 on March 31, 2015, 09:13:40 pm
2^x X 3^x X 3 = 10 (splitting up 3^x+1)(2 X 3)^x = 10/3
2^x X 3^x = 10/3
(2 X 3)^x = 10/3 (Power rule: (ab)^n = a^n x b^n)therefore, log6(10/3) = x
6^x = 10/3
log6^x = log(10/3)
x X log6 = log(10/3)
x = (log(10/3))/(log6)
Post by: keltingmeith on March 31, 2015, 10:09:51 pm
(2 X 3)^x = 10/3
6^x = 10/3
log6^x = log(10/3)
x X log6 = log(10/3)
x = (log(10/3))/(log6)
They are the exact same answer - watch what happens when I change from base 6 to base 10 (with wobblywobbly's answer being base 6, yours being base 10):