Q. A curve is defined by the parametric equations x(t)=7e−8t and y(t)=−7sin(−10t). Find dxdy.
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, let's find dtdx, which is the derivative of x with respect to t. dtdx=dtd[7e(−8t)] Using the chain rule, we get: dtdx=7⋅(−8)⋅e(−8t) dtdx=−56e(−8t)
Calculate dxdy: Next, we find dtdy, which is the derivative of y with respect to t. dtdy=dtd[−7sin(−10t)] Using the chain rule, we get: dtdy=−7×(−10)×cos(−10t) dtdy=70cos(−10t) Since cosine is an even function, cos(−10t)=cos(10t), so we can simplify to: dtdy=70cos(10t)
Simplify expression: Now we have both derivatives:dtdx=−56e−8tdtdy=70cos(10t)To find dxdy, we divide dtdy by dtdx:dxdy=dtdxdtdydxdy=−56e−8t70cos(10t)
Final (dxdy) expression: We can simplify the expression by dividing both the numerator and the denominator by 7:(dxdy)=−8e−8t10cos(10t)
Final (dxdy) expression: We can simplify the expression by dividing both the numerator and the denominator by 7: (dxdy)=−8e−8t10cos(10t)Finally, we can write the simplified expression for (dxdy): (dxdy)=−8e−8t10cos(10t)
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