Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta

P3-vectors watch

Announcements
    • Thread Starter
    Offline

    0
    ReputationRep:
    ORST is a parallelogram, U is the midpoint of RS and V is the midpoint of ST. RElative to the origin O,r,s,t,u,v are posn vectors of R,S,T,U,V respectively.
    Express v in terms of s and t.

    I think v=t+[s/2] and yet the book says [t+s]/2. Why? I mean to get to point V you still have to go the whole length of t, but only half way along ts.
    Attached Images
     
    Offline

    1
    ReputationRep:
    v = t + r/2, not t+s/2, look at the vector OS.
    • Thread Starter
    Offline

    0
    ReputationRep:
    the question says write thw answer in terms of s and t tho....and then back of the book shows [t+s]/2!
    Offline

    1
    ReputationRep:
    (Original post by BossLady)
    the question says write thw answer in terms of s and t tho....and then back of the book shows [t+s]/2!
    Ok, well can u see that it is (t+s)/2?
    Offline

    1
    ReputationRep:
    Do u agree that
    v = t + r/2?

    If so, then see that
    s = OR + RS = r+t

    r = s-t

    So that
    v = t + r/2 = t + (s-t)/2 = (s+t)/2
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by JamesF)
    Do u agree that
    v = t + r/2?

    If so, then see that
    s = OR + RS = r+t

    r = s-t

    So that
    v = t + r/2 = t + (s-t)/2 = (s+t)/2
    ahh i see whta you mean....thanks james. s is OS rather than TS
 
 
 
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?

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.