Find the Unit Tangent Vector of the Given Curve $$r ( t ) = \left( 5 \sin ^ { 3 } 9 t \right) i + \left( 5 \cos ^ { 3 } 9 t \right) \mathbf { j }$$

question 118

Multiple Choice

Find the unit tangent vector of the given curve.
- $$r ( t ) = \left( 5 \sin ^ { 3 } 9 t \right) i + \left( 5 \cos ^ { 3 } 9 t \right) \mathbf { j }$$

• A) T = (5 sin 9t)i - (5 cos 9t)j
• B) T = (sin 9t)i - (cos 9t)j
• C) T = (135 sin 9t)i -(135 cos 9t)j
• D) T = (5 cos 9t)i - (5 sin 9t)j

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