1)

If the vertices  of a triangle are A(0,4,1) ,B(2,3,-1) and C(4,5,0) then the orthocentre of ABC is 


A) (4,5,0)

B) (2,3,-1)

C) (-2,3,1)

D) (2,0,2)

Answer:

Option B

Explanation:

 Vertices of ABC are A(0,4,1) ,B(2,3,-1) and C(4,5,0) 

 AB= (20)2+(34)2+(11)2=4+1+4=3

BC=(42)2+(53)2+(0+1)2=4+4+1=3

and 

CA=(40)2+(54)2+(0+1)2=16+1+4=32

 AB2+BC2=AC2

  ABC is a right angled triangle 

We know that  , the orthocentre of a right angled triangle is the vertex containing the right angle 

Orthocentre is point B(2,3,-1)