Q. A curve is defined by the parametric equations x(t)=−8e−9t and y(t)=sin(−5t). Find dxdy.Answer:
Find dtdx: To find dxdy for parametric equations, we first need to find dtdx and dtdy separately.For x(t)=−8e−9t, we differentiate with respect to t to find dtdx.dtdx=dtd[−8e−9t]Using the chain rule, we get dtdx=−8⋅(−9)⋅e−9tdtdx=72e−9t
Find dtdy: Now, we differentiate y(t)=sin(−5t) with respect to t to find dtdy. dtdy=dtd[sin(−5t)] Using the chain rule, we get dtdy=cos(−5t)⋅(−5) dtdy=−5cos(−5t) Since cosine is an even function, cos(−5t)=cos(5t), so we can simplify this to: dtdy=−5cos(5t)
Calculate dxdy: To find dxdy, we divide dtdy by dtdx. dxdy=dtdxdtdy Substitute the values we found for dtdy and dtdx. dxdy=72e−9t−5cos(5t)
Simplify dxdy: We can simplify the expression for dxdy by dividing both the numerator and the denominator by the common factor if there is any. However, in this case, there is no common factor, so the expression is already in its simplest form.
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