Question

the points A,B and C have coordinates <4,-1,5> and <8,0,6> and <5,-3,3> prove that angle BAC is a right angle.

Answer 1

Find BA nd AC. Then show that BA is perpendicular to AC. Can u?

Answer 2

ive been trying but it seems to end up a mess

Answer 3

Find slope of Ba and AC

Answer 4

I think @ajprincess tried to say that

Answer 5

got any drawing aids there to show me

Answer 6

Thanx for pointing out @sauravshakya

Answer 7

Oh..... wait its a three dimensional figure

Answer 8

yeah

Answer 9

Can we use vector

Answer 10

yes

Answer 11

find BA and AC.
OA=4i-1j+5k, OB=8i+6k and OC=5i-3j+3k
BA=OA-OB
AC=OC-OA
then show that BA.AC=0
I mean show that their dot product is zero.

Answer 12

Can u do @sparksaflyen ?

Answer 13

trying

Answer 14

oh k. if u need help plz ask.

Answer 15

i got 5i-j+k, obviously doing something wrong here, if you got drawing aid please use

Answer 16

make that just 5i-j

Answer 17

u got 4i-j for vat?

Answer 18

I meant to say 5i-j?

Answer 19

obviously wrong

Answer 20

maybe to many u-tube videos from educator is confusing me

Answer 21

again if you got a drawing aid it would help

Answer 22

BA=4i-1j+5k-8i-6k
=-4i-j-k
AC=5i-3j+3k-4i+1j-5k
=i-2j-2k
BA.AC=(-4*1)+(-1*-2)+(-1*-2)
=-4+2+2
=-4+4
=0
So BA is perpendicular to AC.
So <BAC is a right angle.

Answer 23

Is this clear? Plz ask if it os nt clear. Will b back aftr some time.

Answer 24

not clear

Answer 25

why are you putting it the ijk form the coordinates are allready given i'm having trouble plotting these points

Answer 26

example do i go x axis 4, y axis across -1, z axis up 5 and so on

Answer 27

r u askd to plot them?

Answer 28

I am really sorry. i feel it hard to plot them and show u in coordinate system.

Answer 29

thats ok i know how hard it is to draw these things

Answer 30

this was the best i could do to draw them here :P

Answer 31

never mind