Mathematics: Post your doubts here!

[mohmed ahmed soliman]

Watch this:

i am taking math as that seems very advanced but anyway thanks

 

[mohmed ahmed soliman]

Watch this:

i really need a tutiorial for this trigonometry question
what is this trigonometry question i always leave them blank i cant find any useful totorial for this question please forward one tutorial if u have

 

[khan450]

http://justpastpapers.com/wp-content/uploads/2015/10/IMG_6208.jpg
CAN ANY ONE PLEASE HELP ME OUT IN QUESTION NUMBER 7 VECTOR.

 

[khan450]

http://justpastpapers.com/wp-content/uploads/2015/10/IMG_6208.jpg
CAN ANY ONE HELP ME OUT IN Q7 VECTORS part i

 

[osama ahmed ibrahim]

i find diffuclulty to asnwer this trigonometry question
can anyone help


help me in III

 

[The Sarcastic Retard]

View attachment 60414
i really need a tutiorial for this trigonometry questionView attachment 60413
what is this trigonometry question i always leave them blank i cant find any useful totorial for this question please forward one tutorial if u have

Sin theta = opposite/hypotenuse
Sint theta = sqrt(1 - k^2) / 1
sin theta = sqrt(1 - k^2)
As theta is in 4th quadrant, sin theta is negative, thus sin theta = -sqrt(1 - k^2)

tan theta = opposite/adjacent
tan theta = - [sqrt(1 - k^2)]/k

(b) As we know theta is in 4th quadrant as theta is cos theta is positive and theta is reflex angle, so 4th quadrant means theta lies between 270 to 360 degrees. That is 270 < theta < 360. Now we are asked for 2theta so multiply both degress with 2. That is 540 < 2theta < 720. So 540 to 720 degrees both cos theta and tan theta are positive but sin theta is negative. Refrence you can look into above picture.

Hope this helped.

 

[The Sarcastic Retard]

i find diffuclulty to asnwer this trigonometry question
can anyone help
View attachment 60417
View attachment 60418
help me in III

I just explained similar kind in above post. Just know theta lies in which quadrant accordingly solve the question like I explained.
(iii) Sin (theta + pi) = - sin theta <------ This link will be helpful if u know addition formulas, if u dont know it then its in data booklet have a look at it. Moreover if u dont understand that as well, then here is a quick summary to do it, theta is obtuse angle means theta lies in second quadrant that is 90 < theta < 180. So Sin theta is in second quadrant, now if u add more 180 degrees that pi to theta that is sin (theta + pi) obviously ur sin theta will be negative as then theta will lie in III and IV qadrant where sin thet is negative.
so sin theta = k so -sin theta = -k
Thus sin (theta + pi) = -k

 

[mohmed ahmed soliman]

both cos theta and tan theta are positive but sin theta is negative.

i know that in 4th quadrant cos is positive
sin is negative
tan is negative

 

[Evlyn3]

hey! is there anything changed or new in AS/A2 Pure Maths, Statistics 1 and Mechanics 2 for May/June 2016 exams?

 

[The Sarcastic Retard]

i know that in 4th quadrant cos is positive
sin is negative
tan is negative

Oh great! I just wrote down every thing so that if someone else has this doubt, then the one who is replying can tag that person to this link, maybe that person dont know this. ^_^

 

[Shah34]

hi plz help. In these qs they dont consider work done by gravity ie mgsintheta why?????

 

[Spiceangel]

hey, could anyone help me with the following qn part (c)...

 

[TariqBhai]

hey, could anyone help me with the following qn part (c)...

 

[TariqBhai]

Part (ii)

Spiceangel The Sarcastic Retard muhammadali233 farhan141 qwertypoiu Awesome12 *Le me* Akshajistari

 

[Awesome12]

Alright, I get to the equation above but from here the M.S says that the Gradient = -k, which I don't get.
Isn't the gradient = ln y/ x^2
How is it equal to -k?

 

[Copy Cat]

View attachment 60455
View attachment 60456

Alright, I get to the equation above but from here the M.S says that the Gradient = -k, which I don't get.
Isn't the gradient = ln y/ x^2
How is it equal to -k?

lny = lnA + lne^-kx^2
lny= lnA -(kx^2)lne

lne=1

lny=lnA-kx^2

 

[Copy Cat]

 

[farhan141]

View attachment 60466

1st part only. Can u tell me answer of the second?

 

[Copy Cat]

1st part only. Can u tell me answer of the second?

View attachment 60467

 

[qwertypoiu]

View attachment 60468

Spoiler

Edit! :
Once you have k=4/3, you can just proceed directly to tan-1(4/3) = 0.927