English
Hindi
3-1.Vectors
normal

સદિશ $\mathop {\rm{P}}\limits^ \to $   $ \alpha, \beta $ અને $ \gamma  $ સાથે અનુક્રમે $ X, Y$ અને $Z$ ખૂણા બનાવે છે.તો $ {sin^2}\alpha  + {sin^2}  \beta   + {sin^2} \gamma $ =

A

$0$

B

$1$

C

$2$

D

$3$

Solution

${\cos ^2}\alpha \,\, + \;\,{\cos ^2}\beta \,\, + \;\,{\cos ^2}\gamma \, = \,\,1$

$\left( {1\, – \,\,{{\sin }^2}\alpha } \right)\,\, + \;\;\left( {1\,\, – \,\,{{\sin }^2}\beta } \right)\,\, + \;\,\left( {1\,\, – \,\,{{\sin }^2}\gamma } \right)\,\, = \,\,1$

${\sin ^2}\alpha \,\, + \;\;{\sin ^2}\beta \,\, + \;\,{\sin ^2}\gamma \,\, = \,\,3\,\, – \,1\,\, = \,\,2\,$

Standard 11
Physics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.