Turn on thread page Beta
    • Thread Starter
    Offline

    6
    ReputationRep:
    9709/m/j/52/16
    Anyone know how to do (ii)?

    I got an answer for (i) which is 4 m. (−8 = 2x − x^2). I cannot do (ii). Below is the solution for (ii), but I don't understand it at all. How does tan^-1(2) come from? Does 2 come from 8/4 (Sy/Sx)? This does not seem correct to me.

    Also, I am not sure how the picture of this should be looked like? Should it be like the left or the right one? From what I understand, I think it should be the one on the right. However, from the solution, it seems to be the left one that is correct.
    Please help! Thank you
    Attached Images
       
    • Study Helper
    Offline

    15
    Study Helper
    (Original post by anonymo007)
    ...
    For any function y=f(x), dy/dx is the tan of the angle that the curve makes with the +ve x-axis (up being positive).

    So, in this case, dy/dx = 2-2x, which =2 when x=0.

    So, tan of angle of projection = 2. Hence....

    Also,dy/dx > 0 when x=0; so, the curve goes up initially.
    • Thread Starter
    Offline

    6
    ReputationRep:
    (Original post by ghostwalker)
    For any function y=f(x), dy/dx is the tan of the angle that the curve makes with the +ve x-axis (up being positive).

    So, in this case, dy/dx = 2-2x, which =2 when x=0.

    So, tan of angle of projection = 2. Hence....

    Also,dy/dx > 0 when x=0 to the curve goes up initially.
    You have made my day. Thank you so much:wings:
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 8, 2017
Poll
Do you think parents should charge rent?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.