दो सदिशों 6î + 6ĵ - 3k̂ तथा 7î + 4ĵ + 4k̂

Your Ultimate Guide to JEE & NEET Question Solutions

  • Home
  • Solution
  • HI
  • दो सदिशों 6î + 6ĵ - 3k̂ तथा 7î + 4ĵ + 4k̂

दो सदिशों $6\hat i + 6\hat j - 3\hat k$ तथा $7\hat i + 4\hat j + 4\hat k$ के बीच कोण है

A

${\cos ^{ - 1}}\left( {\frac{1}{{\sqrt 3 }}} \right)$

B

${\cos ^{ - 1}}\left( {\frac{5}{{\sqrt 3 }}} \right)$

C

${\sin ^{ - 1}}\left( {\frac{2}{{\sqrt 3 }}} \right)$

D

${\sin ^{ - 1}}\left( {\frac{{\sqrt 5 }}{3}} \right)$

दो सदिशों $6\hat i + 6\hat j - 3\hat k$ तथा $7\hat i + 4\hat j + 4\hat k$ के बीच कोण है

$\cos \theta = \frac{{\overrightarrow A .\overrightarrow B }}{{AB}} = \frac{{42 + 24 - 12}}{{\sqrt {36 + 36 + 9} \sqrt {49 + 16 + 16} }}$$ = \frac{{56}}{{9\sqrt {71} }}$

$\cos \theta = \frac{{56}}{{9\sqrt {71} }}$

$\therefore \sin \theta = \frac{{\sqrt 5 }}{3}$ अथवा $\theta = {\sin ^{ - 1}}\left( {\frac{{\sqrt 5 }}{3}} \right)$