Q. A curve is defined by the parametric equations x(t)=9cos(8t) and y(t)=−3cos(−t). Find dxdy.Answer:
Find dtdx: To find the derivative of y with respect to x (dxdy) for parametric equations, we need to find dtdy and dtdx and then divide dtdy by dtdx. First, let's find dtdx. dtdx=dtd[9cos(8t)] Using the chain rule, the derivative of y0 with respect to y1 is y2 multiplied by the derivative of y3 with respect to y1, which is y5. So, y6
Find dtdy: Now, let's find dtdy. dtdy=dtd[−3cos(−t)] Using the chain rule, the derivative of cos(−t) with respect to t is sin(−t) multiplied by the derivative of −t with respect to t, which is −1. So, dtdy=3sin(−t) Since dtdy0, we can simplify this to dtdy1
Calculate dxdy: Now that we have both derivatives, we can find dxdy by dividing dtdy by dtdx. dxdy=dtdxdtdy Substitute the values we found for dtdy and dtdx. dxdy=−72sin(8t)−3sin(t)
Simplify expression: We can simplify the expression by dividing both the numerator and the denominator by −3sin(t).(dxdy)=24sin(8t)sin(t)However, this simplification assumes that sin(t) is not zero, as division by zero is undefined. Since sin(t) can be zero for some values of t, we must be careful not to cancel out terms that could lead to division by zero. In this case, we can proceed with the simplification because we are looking for a general expression for (dxdy), not its value at specific points.
Final derivative: The final step is to simplify the expression further if possible. However, without additional information about the relationship between sin(t) and sin(8t), we cannot simplify the expression any further.Therefore, the derivative of y with respect to x, given the parametric equations, is:(dxdy)=24sin(8t)sin(t)
More problems from Write a quadratic function from its x-intercepts and another point