The value of b such that the scalar product of the vector ^i+^j+^k with the unit vector parallel to the sum of the vectors 2^i+4^j+5^k and b^i+2^j+3^k is one, is
A
-2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
-1
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
1
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution
The correct option is C 1 The unit vector parallel to the sum of the vectors 2^i+4^j−5^k and b^i+2^j+3^k is ^n=(2+b)^i+6^j−2¨k√(2+b)2+62+(−2)2=(2+b)^i+6^j−2¨k√b2+4b+44 Now,(^i+^j+^k).^n=1 ⇒2+b+6−2=√b2+4b+44⇒b=1