question_answer

Find the values of x for which the angle between the vectors \[\overrightarrow{a}=2{{x}^{2}}\,\hat{i}+4\,x\hat{j}+\hat{k}\] and \[\overrightarrow{b}=7\,\hat{i}-2\hat{j}+x\hat{k}\]  is Obtuse.

A)  \[0<x<\frac{1}{2}\]    

B)  \[0<x<1\]

C)  \[0<x<\frac{1}{3}\]                

D)  \[0<x<\frac{1}{4}\]

E)  None of these