BT STS

Q1. A and B are points with coordinates (2,1,3) and (4,-2,5) respectively. 2x+y-z=3 is the equation of a plane

(A) Line AB is parallel to the plane
(B) AB meets the plane at (0,4,1)
(c) The plane divides AB externally in the ration 1:2
(D) A and B are on the same side of the plane

MULTI ANSER

Q2. matrix
\vec{a} and \vec{b} are two unit vectors inclined at an angle \theta to each other. Then
\begin{matrix} \textup{Column 1} & \textup{Column 2}\\ (A)\; \left|\vec{a} +\vec{b}\right| < \sqrt{2} & (p)\; 2\pi /3<\theta <\pi \\ (B)\; \left|\vec{a} -\vec{b}\right| < \sqrt{2} & (q)\; \pi /3<\theta <\pi/2\\ (C)\; \left|\vec{a} +\vec{b}\right| < 1 & (r)\; \pi /2<\theta <\pi\\ (D)\; 1<\left|\vec{a} -\vec{b}\right| < \sqrt{2}& (s)\; 0<\theta <\pi/3\\ & (t)\; 0 <\theta <\pi /2 \end{matrix}

8 Answers

1
rahul nair ·

2.
A-pr
B-qst
C-p
D-q

106
Asish Mahapatra ·

exactly my answr as well

but they have provided ans as
A-r
B-t
C-p
D-q

so in answering such type of questions, is it necessary that only the full, complete interval will be tha answer ... or any subset of that can also be the anser??

29
govind ·

Ans1...B,C,D..

106
Asish Mahapatra ·

my ans also BCD

but provided BC only....

1
rahul nair ·

yeah ,even I have problems with the solns provided by BT.............
Even I have the same doubt,if such n ques come in JEE, what should we mark???

1
rahul nair ·

1.even I got BCD.......

29
govind ·

D shud true if C is true..coz if the plane divides the line segment externally then..it is sure that those points lie on the same side of the plane...Btw is there any reason given for the answers by them??

106
Asish Mahapatra ·

they calculated ration as -1/2

and say that hence C is true and D false

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