STPM: Math T/S Paper 1 Integration

[Sammillau]

pls help me to solve this.........my school exam question

integrate ln(x+2) (5 marks)

[uoykcuf]

try integration by part :D
int ln(x+2)= int 1.ln(x+2)=......

[lawteoh]

I think that question is quite basic.. yeah, integrate by parts. Let u=1 and dv/dx=ln(x+2). I am sure u noe the formula right? Then solve it. =)

[sTuPiDdgAl]

hi....pls help me to solve this question...thanks!!!

Mathematics T
No.1.Solve the following simultaneous equations:

2^x - 5^y = 3

2^x-3 + 5^y-2 = 21

[ChristopherCWL]

hi....pls help me to solve this question...thanks!!!

Mathematics T
No.1.Solve the following simultaneous equations:

2^x - 5^y = 3

2^x-3 + 5^y-2 = 21

Try to get the value of 2^x by dragging the 5^y towards the right side...then substitute it into the number two equation...be sure to open the 2^X-3 first....

* im not pretty sure this really works if there are anythings wrong, please correct me..

[lawteoh]

hi....pls help me to solve this question...thanks!!!

Mathematics T
No.1.Solve the following simultaneous equations:

2^x - 5^y = 3

2^x-3 + 5^y-2 = 21

quite easy.. y =3 and x = 7.

for the second equation, just put 1/8 (2^x) + 1/25 (5^y) = 21 .. I put this as equation 3.

From equation 1, u can rearrange it to become 3 + 5^y = 2^x ..... equation 4

substitute 4 into 3.

1/8 ( 3+ 5^y) +1/25 (5^y) = 21

in the end, u will get 5^y = 1425/11

y = 3 .. then u shud noe how to get x..

[youngyew]

For some problems, you can now get the solutions and the working easily in Wolfram|Alpha :)

http://www.wolframalpha.com

For example:

integrate ln(x+2) - Wolfram|Alpha (http://www90.wolframalpha.com/input/?i=integrate+ln%28x%2B2%29&asynchronous=false&equal=Submit)

[markwongsk]

hi....pls help me to solve this question...thanks!!!

Mathematics T
No.1.Solve the following simultaneous equations:

2^x - 5^y = 3

2^x-3 + 5^y-2 = 21

Another method which I find quite useful teaching students is:

Let 2^x = a and 5^y = b

Therefore a - b = 3

and a/8 + b/4 = 21

I'm sure you can solve this =) just don't forget to find x and y!

[anbbly]

quite easy.. y =3 and x = 7.

for the second equation, just put 1/8 (2^x) + 1/25 (5^y) = 21 .. I put this as equation 3.

From equation 1, u can rearrange it to become 3 + 5^y = 2^x ..... equation 4

substitute 4 into 3.

1/8 ( 3+ 5^y) +1/25 (5^y) = 21

in the end, u will get 5^y = 1425/11

y = 3 .. then u shud noe how to get x..
i don noe where m i wrong..pls correct me..
1/8 ( 3+ 5^y) +1/25 (5^y) = 21
2.5^y=(21x200)-3
5^y=4197/2
then i use log to find out y..d answer is y=4.75

== i m nt talent in math T..sobb..:(

[markwongsk]

i don noe where m i wrong..pls correct me..
1/8 ( 3+ 5^y) +1/25 (5^y) = 21
2.5^y=(21x200)-3
5^y=4197/2
then i use log to find out y..d answer is y=4.75

== i m nt talent in math T..sobb..:(

When you multiplied the left by 200, you need to know that you only multiply 1/25 by 200 therefore it should be

25 (3+5^y) + 8 (5^y) = 21X200

[anbbly]

When you multiplied the left by 200, you need to know that you only multiply 1/25 by 200 therefore it should be

25 (3+5^y) + 8 (5^y) = 21X200
opps..i forget to times d upper parts as well..:P
paiseh..wat a careless mistake..:notrust
thx =)

[ChristopherCWL]

Another method which I find quite useful teaching students is:

Let 2^x = a and 5^y = b

Therefore a - b = 3

and a/8 + b/4 = 21

I'm sure you can solve this =) just don't forget to find x and y!

Buddy!! THX!!! u helped me alot even though im not asking this question!! i like ur method!! it is very useful to me :) WEll done Teacher!!!