Q. Let x and y be functions of t with y=2x3+4x2+3. If dtdx=31, what is dtdy when x=4?Write an exact, simplified answer.
Identify Function: Identify the function and differentiate it with respect to x. Given y=2x3+4x2+3, differentiate each term with respect to x. dxdy=6x2+8x
Apply Chain Rule: Apply the chain rule to find dtdy. Using dtdy=(dxdy)⋅(dtdx), substitute dtdx=31. dtdy=(6x2+8x)⋅(31)
Substitute x=4: Substitute x=4 into the expression for dtdy. dtdy=(6∗(4)2+8∗4)∗(31) dtdy=(6∗16+32)∗(31) dtdy=(96+32)∗(31) dtdy=128∗(31) dtdy=42.67
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