W00t! I did question 10... (1 Viewer)

[smallcattle]

I couldnt get the very last question of Q10b

can someone explain??

 

[Jezzabelle]

hehehe...but failed all the other questions though

and i quote: "All questions are of equal value"

 

[acmilan]

Using the z equation you found in (ii), sub in the x value of (iii). Now after simplification you will find z = root(bc - bccosA) and then you must find cosA using the large triangle ABC using the cos rule, sub the value for cosA into the equation of z and after some manipulations you will get what you need

 

[smallcattle]

Using the z equation you found in (ii), sub in the x value of (iii). Now after simplification you will find z = root(bc - bccosA) and then you must find cosA using the large triangle ABC using the cos rule, sub the value for cosA into the equation of z and after some manipulations you will get what you need

arhh.... damn it.....i forgot to solve cos A

i was like cancelling, dividng, multiplying and stuff, and i thought wtf, how do i cancel cosA to get the fina answer....

 

[euphoric]

Since Area(AST)=Area(BCST) then

Area(ABC)=2Area(AST)

1/2(bcsinA) = 2.1/2(xysinA)

1/2(bcsinA) = xysinA

hence xy = 1/2(bc)

are u seirous?
thats soo easy! and i couldnt figure it out in the exam
blha~ i only left that question out. besides that question ten was good!

 

[angelduck]

yes! i managed to do that bit right!!!

Just for interest, could someone post how to do Q 10, the 4 marks bit and last bit, I got most of it out, but couldnt finish

 

[skankit]

10B iii was good. all u had to do was differentiate it twice and then sub in the x value

you didnt need to differentiate it twice, only once. you just leave it as z2 and differentiate that, and then let it equal 0 to find the minimum

i got the last part, but i didnt know how to factorise it thank god for them giving it in the question!!!]

i couldnt do the last part of 8b) i ended up with like 17 1/3 or something, i did all this hard core tricky intergration then i got and realised how easy it is

stupid maths

and i coudlnt for the life of me do question 5b iv.. i kept getting v=0... in the end i got something random which im positive wasnt right