Under which condition will the magnitude of the resultant of two vectorsbe equal to that of any one of theconstituent vectors ?

Under which condition will the magnitude of the resultant of two vecto

1.	Under which condition will the magnitude of the resultant of two vectorsbe equal to that of any one of theconstituent vectors ?
Answer» Solution :Suppose, a and b are the magnitudes of two vectors and the angle between them is `theta` . ACCORDING to the problem let the MAGNITUDE of theresultant of `veca and vecb` be EQUAL to a . Therefore, `a^2=a^2+b^2+2abcos theta or, b(b+2a cos theta)=0` `therefore b+2acos theta=0[because b ne0]` or, `theta = cos^(-1)(-b/(2a))` that is , if the angle between `veca and vecb` is =`cos^(-1)(-b/(2a)) or cos^(-1)(-a/(2b))`, the magnitude of the resultant vector is equal to a or b respectively.