Find the angle between the vectors `vecr_(1)=(3hati-2hatj+hatk) and hatr_(2)=(4hati+5hatj+7hatk)`.

Answer

`cos^(-1)""((3)/(2sqrt35))`

Explanation

`costheta=(vecr_(1)*vecr_(2))/(|vecr_(1)||vecr_(2)|)=((3hati-2hatj+hatk)*(4hati+5hatj+7hatk))/({sqrt(3^(2)+(-2)^(2)+1^(2))}{sqrt(4^(2)+5^(2)+7^(2))})=(3)/(2sqrt35)`.