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  • The angle between A=\hat{i}+\hat{j} and B=\hat{i}-\hat{j} is (a) 45^{o} (b) 90^{o} (c) -45^{o} (d)180^{o}

The angle between A=\hat{i}+\hat{j} and B=\hat{i}-\hat{j} is

(a) 45^{o}

(b) 90^{o}

(c) -45^{o}

(d)180^{o}

Answers (1)

The answer is the option  (b), 90^{o}

Explanation :

We know from the formula that A.B=\left \| A \right \|\left \| B \right \|\cos \theta

Given that \vec{A}=\hat{\iota }+\hat{J} and \vec{B}=\hat{\iota }-\hat{J}

\cos \theta =\frac{(\hat{\iota }+\hat{J})(\hat{\iota }-\hat{J})}{\sqrt{1^{2}+1^{2}}(\sqrt{1^{2}+(-1^{2})})}

=0=\cos 90

Hence the angle is 90^{o}

Posted by

infoexpert24

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