Mathematics: Post your doubts here!

[Anum96]

http://papers.gceguide.com/A Levels/Mathematics (9709)/9709_s15_qp_22.pdf
Q1)(ii) I got least value as -21.6 and greastest as 21.6 so how n can be 43?
Q3(i) why tan theta cant be negative 4?
Q4(i) I got dy/dx = e^x - 8e^-2x. Now how to solve this when dy/dx = 0?
I did like this,
e^x(1 - 8e^-3x) = 0
ln (1/8) = -3x.
Then is it like, x = ln(1/8) / -3 ?
Q5(ii)(iii) No idea.
Thanks.
Anum96 See if u can help me. ^_^

Q3 (i) tan theta cant be negative because the qs says its an acute angle. tan 4 gives you 75.96 and since tan is negative in second and forth quadrant, your ans is 180 - 75.96 i.e. 104.04 which is in no way acute.
Q4 (i) dy/dx = e^x - 8e^-2x
Take e^x common
e^x(1 - 8e^-3x)=0
- 8e^-3x = - 1
e^-3x = 1/8
ln e^-3x = ln (1/8)
-3x lne = ln(1/8)
x = [ln(1/8)/-3)
x = 0.69314718 = ln2
Q5(ii) In these type of questions youre usually given with x1 value. If not just assume it to be 1
So put x equals 1 in the equation and keep solving like you solve other iterations. You will start getting 1.8038 consecutively and so this will be your answer. Rounding off will give you 1.804
(iii)Now use the ans to part (ii) for this part. Find the corresponding y value and that will be your answer. But remember there will be 2 answers since there are two intersecting points. One with positive x value and the other with negative

 

[The Sarcastic Retard]

Q3 (i) tan theta cant be negative because the qs says its an acute angle. tan 4 gives you 75.96 and since tan is negative in second and forth quadrant, your ans is 180 - 75.96 i.e. 104.04 which is in no way acute.
Q4 (i) dy/dx = e^x - 8e^-2x
Take e^x common
e^x(1 - 8e^-3x)=0
- 8e^-3x = - 1
e^-3x = 1/8
ln e^-3x = ln (1/8)
-3x lne = ln(1/8)
x = [ln(1/8)/-3)
x = 0.69314718 = ln2
Q5(ii) In these type of questions youre usually given with x1 value. If not just assume it to be 1
So put x equals 1 in the equation and keep solving like you solve other iterations. You will start getting 1.8038 consecutively and so this will be your answer. Rounding off will give you 1.804
(iii)Now use the ans to part (ii) for this part. Find the corresponding y value and that will be your answer. But remember there will be 2 answers since there are two intersecting points. One with positive x value and the other with negative

Thank you. Well I never solved questions for iterations before. Which chapter is this? Can u temme, so that I can refer to that chapter.. Thanks.. and so I didnt get the explanation f Q5.
I kept x =1 then 2 then 3, I got different answers. :/ Was I supoose to do this?? I never got 1.804
What about Q1?

 

[Anum96]

Thank you.
What about Q1?

Count the numbers/integers falling in between your answers. Remember to count -21, 21 and 0
43

 

[The Sarcastic Retard]

Count the numbers/integers falling in between your answers. Remember to count -21, 21 and 0
43

I dont get it

 

[The Sarcastic Retard]

Thank you. Well I never solved questions for iterations before. Which chapter is this? Can u temme, so that I can refer to that chapter.. Thanks.. and so I didnt get the explanation f Q5.
I kept x =1 then 2 then 3, I got different answers. :/ Was I supoose to do this?? I never got 1.804
What about Q1?

Anum96 Also in Q6 how do we know we have to give answer in radian form?

 

[Anum96]

Anum96 Also in Q6 how do we know we have to give answer in radian form?

First, do me a favor. Please change your avatar. My alerts bar looks scary af. No offence intended.

 

[The Sarcastic Retard]

First, do me a favor. Please change your avatar. My alerts bar looks scary af. No offence intended.

Sorry, I can't do this favor. Help if u want to.

 

[Anum96]

Anum96 Also in Q6 how do we know we have to give answer in radian form?

As for your question. Its better if you give your answer in both forms. I always gave two answers to be on the safe side. However, One things for sure. Whenever the question is in terms of pi, you're supposed to give it in radians.

 

[The Sarcastic Retard]

As for your question. Its better if you give your answer in both forms. I always gave two answers to be on the safe side. However, One things for sure. Whenever the question is in terms of pi, you're supposed to give it in radians.

Thanks.

 

[Anum96]

Anum96 Also in Q6 how do we know we have to give answer in radian form?

You put x as 1. Correct. Now use this value as x.
For e.g you got 0.354 when x is 1. now put 0.354 as x and so on. You have to keep using your answers. Thats how you solve iterations.

 

[The Sarcastic Retard]

You put x as 1. Correct. Now use this value as x.
For e.g you got 0.354 when x is 1. now put 0.354 as x and so on. You have to keep using your answers. Thats how you solve iterations.

how much times do we do that?

 

[Anum96]

how much times do we do that?

The moment you get the same answer thrice

 

[Anum96]

Answers are usually pretty long. Make sure you use the whole answers, no matter how long they are. Let your calculator handle that.

 

[The Sarcastic Retard]

The moment you get the same answer thrice

Thanks a lot.

 

[Anum96]

Sorry, I can't do this favor. Help if u want to.

K,bro!

 

[Anum96]

http://papers.gceguide.com/A Levels/Mathematics (9709)/9709_s15_qp_22.pdf
Q1)(ii) I got least value as -21.6 and greastest as 21.6 so how n can be 43?
Q3(i) why tan theta cant be negative 4?
Q4(i) I got dy/dx = e^x - 8e^-2x. Now how to solve this when dy/dx = 0?
I did like this,
e^x(1 - 8e^-3x) = 0
ln (1/8) = -3x.
Then is it like, x = ln(1/8) / -3 ?
Q5(ii)(iii) No idea.
Thanks.
Anum96 See if u can help me. ^_^

Why do u keep editing your messages? I wouldn't have given you the same detail you know.

 

[The Sarcastic Retard]

Why do u keep editing your messages? I wouldn't have given you the same detail you know.

Look, I edited that post so that u would have less to work...
I will get nothing to make u fall in trouble...

you know what i have also helped to so many ppl and if they did this, I never said this things... anyways sorry to trouble.

 

[Anum96]

Look, I edited that post so that u would have less to work...
I will get nothing to make u fall in trouble...

you know what i have also helped to so many ppl and if they did this, I never said this things... anyways sorry to trouble.

Lol. Whatever. Its Ok.

 

[Mr.Physics]

Q 13b
Anum96

 

[Mr.Physics]

-17.4?

For which one ?