Question

angle between the vector 3i+j+2k and i+j+k​

Answer 1

Answer:

let the angle made by them is x°

Step-by-step explanation:

|3i+j+2k|=√(3²+1²+2²)

=√(14)

and,

|i+j+k|=√(1²+1²+1²)

=√3

ab=√(a²+b²+2abcosx⁰)

a=√14

b=√3

so,

√14×√3=✓(√14²+√3²+2×√14×√3×cosx⁰)

√42=√(14+3+2√42×cosx⁰)

(squaring on both sides)..(so roots will cancel)

42=17+2√42×cosx⁰

=>cosx⁰=25/2√42

x⁰=cos^-1(25/2√42)