Q. A curve is defined by the parametric equations x(t)=−4cos(−5t) and y(t)=3sin(−8t). Find dxdy.Answer:
Find dtdx: To find dxdy for parametric equations, we need to find dtdy and dtdx separately and then divide dtdy by dtdx.
Find dtdy: First, we find dtdx. The derivative of x(t)=−4cos(−5t) with respect to t is dtdx=−4⋅dtd[cos(−5t)]. Using the chain rule, we get dtdx=−4⋅(−5)⋅(−sin(−5t))=20sin(−5t).
Divide to find dxdy: Next, we find dtdy. The derivative of y(t)=3sin(−8t) with respect to t is dtdy=3⋅dtd[sin(−8t)]. Using the chain rule, we get dtdy=3⋅(−8)⋅cos(−8t)=−24cos(−8t).
Simplify the expression: Now we divide dtdy by dtdx to find dxdy.dxdy=dtdxdtdy=20sin(−5t)−24cos(−8t).
Simplify the expression: Now we divide dtdy by dtdx to find dxdy. dxdy=dtdxdtdy=20sin(−5t)−24cos(−8t).We can simplify the expression by dividing both the numerator and the denominator by 4. dxdy=5sin(−5t)−6cos(−8t).
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