If a =4i ˆ+6j ˆ and b =3j ˆ+4k ˆ, then the vector form of the component of a along b is
(a) 18/5 (3i ˆ+4k ˆ ) (b) 18/25 (3j ˆ+4k ˆ )
(c) 18/5 (3i ˆ+4k ˆ ) (d) 18/25(4i ˆ+6j ˆ)
CBSE Class 12 Sample Paper for 2024 Boards
CBSE Class 12 Sample Paper for 2024 Boards
Last updated at August 4, 2026 by Teachoo
Transcript
Now, Vector component of š ā along š ā = Projection Ć Unit vector of š ā = š/("|" š ā"|" ) (š ā. š ā) Ć š ā/(|š ā|) = ((š ā". " š ā)/ć\ |š ā|ć^2 ) š ā ) Now, š ā = 4š Ė+6š Ė = šš Ė+šš Ė + 0 š Ė š ā = 3š Ė+4š Ė = 0š Ė + šš Ė+šš Ė Finding š ā. š ā (š ā. š ā) = (4 Ć 0) + (6 Ć 3) + (0 Ć 4) = 0 + 18 + 0 = 18 Magnitude of š ā = ā(02+32+42) |š ā | = ā(0+9+16) = ā25 = 5 Now, Vector component of š ā along š ā = ((š ā". " š ā)/ć\ |š ā|ć^š ) š ā = 18/ć\ 5ć^š (3š Ė+4š Ė) = šš/šš (šš Ė+šš Ė ) So, the correct answer is (b)