ne plus ultra
New Member
- Joined
- Sep 27, 2006
- Messages
- 26
- Gender
- Female
- HSC
- 2007
when i did intergration questions, i did it like this, for example:
intergral tanx dx
('intergral' here means the symbol...the big 's' like symbol....i dont know how to type in....||||- -)
then this is what i did:
intergral tanx dx
=intergral sinx dx/cosx
=intergral - d cosx/cosx
= - ln cosx + C
done.
my teacher says she never met anything like 'd cosx' here, so that i can't use it in doing the questions. instead we have to strictly follow the differenciate step which is:
dy=sinx dx
therefore dy/dx=sinx
therefore y=-cosx
however in my opinion, the only different between what i did and what the teacher said, is that she sub a 'y' as a medium in doing the question while i didnt. anyway both of us got the correct answer.
my teacher told me i must lose marks in HSC and i d better never use that again. i dont know how come mine is incorrect in the exam. isnt our purpose to solve the questions but not the from we write? i have use such a method for more than one year and nobody tell me it is not right...suddenly force me to change my brian make me extraodinarily uncomfortable.......- -
i need somebody who KNEW the HSC VERY MUCH to tell me if i can do 'd cosx' things in the exam.
(sorry for my messy english....><)
THANK YOU SOOO MUCH.......
intergral tanx dx
('intergral' here means the symbol...the big 's' like symbol....i dont know how to type in....||||- -)
then this is what i did:
intergral tanx dx
=intergral sinx dx/cosx
=intergral - d cosx/cosx
= - ln cosx + C
done.
my teacher says she never met anything like 'd cosx' here, so that i can't use it in doing the questions. instead we have to strictly follow the differenciate step which is:
dy=sinx dx
therefore dy/dx=sinx
therefore y=-cosx
however in my opinion, the only different between what i did and what the teacher said, is that she sub a 'y' as a medium in doing the question while i didnt. anyway both of us got the correct answer.
my teacher told me i must lose marks in HSC and i d better never use that again. i dont know how come mine is incorrect in the exam. isnt our purpose to solve the questions but not the from we write? i have use such a method for more than one year and nobody tell me it is not right...suddenly force me to change my brian make me extraodinarily uncomfortable.......- -
i need somebody who KNEW the HSC VERY MUCH to tell me if i can do 'd cosx' things in the exam.
(sorry for my messy english....><)
THANK YOU SOOO MUCH.......