IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Math => Topic started by: zabady on May 02, 2010, 06:46:44 pm

Title: c4 vectors quick question
Post by: zabady on May 02, 2010, 06:46:44 pm: i want part C
Title: Re: c4 vectors quick question
Post by: astarmathsandphysics on May 02, 2010, 07:34:00 pm: When i get home. On a phone now.
Title: Re: c4 vectors quick question
Post by: T.Q on May 02, 2010, 08:43:54 pm: for part c

distance $PQ=\sqrt{90}$

$R= (1+3s)i + (4+s)j+(2)k$

so

distance $PR=\sqrt{10s^2 }$

PQ=PR

$\sqrt{90}=\sqrt{10s^2 }$

Squer both sides

$90=10s^2$

$s=\pm3$

now substitute S in L2

and find the coordinates