What is the scalar product of -2i+3j+4k and 5i-3j+3k, where I, j and k are the Cartesian unit vectors? answers given A,-15. B,-10. C, -7. D, 7. E, 10. ?

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Answer 1 · 2018-08-14T21:26:58

#veca*vecb=-7toC#

We know that,

#"If "vecx=(x_1,x_2,x_3) and vecy=(y_1,y_2,y_3) ,#

# "then scalar(dot) product of " vecx and vecy# is :

#color(red)(vecx*vecy=x_1y_1+x_2y_2+x_3y_3.#

Let

#veca=-2i+3j+4k=<-2,3,4>#

#vecb=5i-3j+3k=<5,-3,3>#

#:.veca*vecb=<-2,3,4> * <5,-3,3>#

#:.veca*vecb=(-2)(5)+(3)(-3)+(4)(3)#

#:.veca*vecb=-10-9+12#

#:.veca*vecb=-7#