Problem

Find the angle between vectors u=(3,4,0) and v=(2,1,2) using the cross product.

Answer

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Answer

The angle θ between the vectors can be found using the formula sinθ=u×vuv. Substituting the computed values, we get sinθ=8953=8915. Thus, θ=arcsin(8915).

Steps

Step 1 :First, calculate the cross product of u and v. The cross product of u and v is given by u×v=(u2v3u3v2,u3v1u1v3,u1v2u2v1). Substituting the given values, we get u×v=(4(2)01,023(2),3142)=(8,6,5).

Step 2 :The magnitude of a vector x=(x1,x2,x3) is given by x=x12+x22+x32. Applying this, we get u=32+42+02=5 and v=22+12+(2)2=3. The magnitude of the cross product u×v=(8)2+62+(5)2=89.

Step 3 :The angle θ between the vectors can be found using the formula sinθ=u×vuv. Substituting the computed values, we get sinθ=8953=8915. Thus, θ=arcsin(8915).

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