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Find the angle between the lines ` vec r=2 hat i-5 hat j+ hat k+lambda(3 hat i+2 hat j+6 hat k)`and ` vec r=7 hat i-6 hat k+mu( hat i+2 hat j+2 hat k)dot` |
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Answer» Correct Answer - `cos^(-1) ((19)/(21))` the angle between the lines and `vec(r ) = a_(1) + lambda b_(1) " and " vec(r )=vec(a)_(2) + lambda b_(2) ` is given by `" cos " theta =(vec(b)_(1).vec(b)_(2))/(|vec(b)_(1)||vec(b)_(2)|)` `:. " cos " theta =(|(3hat(i) +2hat(j) +6hat(k)).(hat(i) +2hat(j) +2hat(k))|)/{{sqrt(sqrt(3^(2)+2^(2)+6^(2)))}{sqrt(1^(2)+2^(2)+2^(2))}} =((3 +4 +12))/((7xx3)) =(19)/(21)` `rArr theta = " cos "^(-1) ((19)/(21))` |
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