Question

The parametric curve r=(2t2+8t−5,−2cos(πt),t3−28t)r=(2t2+8t−5,−2cos⁡(πt),t3−28t) crosses itself at one and only one point. The point is (x,y,z)=(x,y,z)= ( , , ). Let θθ be the acute angle between the two tangent lines to the curve at the crossing point. Then cos(θ)=cos⁡(θ)=

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Answer 1

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