Mathematics: Post your doubts here!

[shanky631]

ln (x+2) - ln x = 2
ln ((x + 2) / 2) = 2
(x + 2) / 2 = e^2


x + 2 = 2 e^2
x = 2 (e^2 - 1)

but u not getting the right answer. and shouldn't it be ln((x+2)/x)=2

 

[shanky631]

i think that is the only mistake. Rest is right. Thank u smzimran.

 

[Minato112]

ln (x+2) - ln x = 2
ln ((x + 2) / 2) = 2
(x + 2) / 2 = e^2


x + 2 = 2 e^2
x = 2 (e^2 - 1)

but u not getting the right answer. and shouldn't it be ln((x+2)/x)=2

ln ((x + 2) / x) = 2
(x + 2) / x = e^2
x+2= (e^2)*x
((e^2)*x)-x=2
x((e^2)-1) = 2
x = 2/ ((e^2)-1)
= 0.313

 

[smzimran]

ln ((x + 2) / x) = 2
(x + 2) / x = e^2
x+2= (e^2)*x
((e^2)*x)-x=2
x((e^2)-1) = 2
x = 2/ ((e^2)-1)
= 0.313

i think that is the only mistake. Rest is right. Thank u smzimran.

Yes, i did a little mistake, copied 2 in the denominator instead of x, rest is right!
minato112 has done the correct method, check it out!

 

[shanky631]

statistics Chapter 2 doubt. How to solve Q1???

 

[shanky631]

statistics Chapter 2 doubt. How to solve Q1???

the ans is 0.0592, incase someone gets plz post the workings.

 

[Lyfroker]

That's a hard one!
Maybe it has to do with parametric equations, don't u think?

points lieing on a circle means the distance from the centre to these points will be same.
check that out prove that out.

A quick search on Google gave me this: http://www.mymathforum.com/viewtopic.php?t=23065&p=92079

If the three points lie on the circumference of a circle there distances from the centre (2,0) must be same [RADIUS ]

Find the distance b/w (7,12) and (2,0)

Find the distance b/w (-3,-12) and (2,0)

Find the distance b/w (14,-5) and (2,0)

These three distances must be same!

tnx 4 ur help guys i solved it myself, smzimran yh they r all radius

 

[parthrocks]

statistics Chapter 2 doubt. How to solve Q1???

anyone der to solve plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

 

[parthrocks]

can anyone plzzz help me out with question 2 and question 3.....when i tried and did it.....my answer is nt matching with the textbook answers help

 

[parthrocks]

can anyone plzzz help me out with question 2 and question 3.....when i tried and did it.....my answer is nt matching with the textbook answers help

link image:-
http://www.xtremepapers.com/community/attachments/img_0296-jpg.13983/

 

[celoth]

can anyone plzzz help me out with question 2 and question 3.....when i tried and did it.....my answer is nt matching with the textbook answers help

question 2 answer is it 0.496?
question 3 answer is it 0.1587?

 

[GorgeousEyes]

Please could you sketch and explain them : 1) 4sin(3x) ,0 (<or =) x ( <or=) 360
2) 9-5cos(2x) , 0 (<or =) x ( <or=) 360
3) 3+4sin(2x) , 0 (<or =) x ( <or=) 180
4)Tan(2x) , 0 (<or =) x ( <or=) 180

Thanks alot !

 

[shanky631]

can someone show me how to work this out?

 

[shanky631]

can someone show me how to work this out?
View attachment 14019

Q8) part b

 

[shanky631]

Q8) part b

the ans 0.72, 5.56, 3.141

 

[VelaneDeBeaute]

Please could you sketch and explain them : 1) 4sin(3x) ,0 (<or =) x ( <or=) 360
2) 9-5cos(2x) , 0 (<or =) x ( <or=) 360
3) 3+4sin(2x) , 0 (<or =) x ( <or=) 180
4)Tan(2x) , 0 (<or =) x ( <or=) 180

Thanks alot !

Aoa! Why don't you go to http://www.wolframalpha.com/ and check out the graphs for yourself? But if you're unsuccessful, your welcome back to carry this query forward!

 

[VelaneDeBeaute]

"Integration A2"

So there's this question on how to integrate cos^3 x. I did it by breaking it into cos^2 x and cos x, you know, the by-parts method. But i seem to be getting the wrong answer. Could anyone do it for me, so i could compare my working ?? Thankyou!

 

[smzimran]

"Integration A2"

So there's this question on how to integrate cos^3 x. I did it by breaking it into cos^2 x and cos x, you know, the by-parts method. But i seem to be getting the wrong answer. Could anyone do it for me, so i could compare my working ?? Thankyou!

AoA,
This is best done using substitution, and not by parts:

 

[celoth]

"Integration A2"

So there's this question on how to integrate cos^3 x. I did it by breaking it into cos^2 x and cos x, you know, the by-parts method. But i seem to be getting the wrong answer. Could anyone do it for me, so i could compare my working ?? Thankyou!

cos^3 x
= (cos^2 x)(cos x)
= (1-sin^2 x)(cos x)
= cos x - (sin^2 x)(cos x)

after integration,
it become:
= -sin x - (1/3)(sin^3 x) + c

 

[JulyMei]

Can anyone help me in this question?

Thanks in advance.