Gujarati
3-1.Vectors
medium

दो सदिशों $ - 2\hat i + 3\hat j + \hat k$ तथा $\hat i + 2\hat j - 4\hat k$ के बीच कोण ....... $^o$ है

A

$0$

B

$90$

C

$180$

D

उपरोक्त में से कोई नहीं

Solution

(b) $\cos \theta = \frac{{\overrightarrow {\;A} .\overrightarrow {\;B} }}{{|\overrightarrow {\;A} ||\overrightarrow {\;B} |}} = \frac{{ – 2 + 6 – 4}}{{\sqrt {14} \sqrt {21} }} = 0$

$⇒$ $\theta = 90^\circ $

Standard 11
Physics

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