help on the 2000 hsc paper (1 Viewer)

[vampiros]

question 7 part b part iv

i cannot find the "right" answer anywhere. i have a past papers book. and ive had a look at the solutions on this site. both of them appear to be wrong.

the solution refers to substituting a value for x. except that instead of using a cos^2(alpha) they use cos(alpha). which makes the answer a hell of a lot easier... and it comes out to being correct, though it worries me that i cant see another way to do it.

does anyone know the right answer? or why they did what they did in theirs? could you send the answer to geoffros_blade@hotmail.com before tuesday if possible? (thats when my exams is).

thanks

 

[Rahul]

u might want to post the question, as not everyone is going to have the hsc 2000 paper.

 

[vampiros]

sorry . lol

ok the question is too involved for me to type it all out to a post. so ill give the urls to the question and answer..

question: Question 7 Part b part iv (Projectile Motion)

http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2000exams/hsc00_maths/00mathematics34U.pdf

solution:

http://www.boredofstudies.org/courses/maths/3u/2000_Maths3_HSC_BOS_s.pdf

the mistake i Think that is there, is directly under the line where it says: "the slope of the direction at impact is given"