Q. 3 The equation of the curve is y=3+4xe2x.(i) Find the coordinates of the stationary point on the curve, leaving your answer in exact value.
Quotient Rule Application: To find the derivative, we use the quotient rule: v2v(u′)−u(v′), where u=e2x and v=3+4x.
Derivative of u: Differentiate u with respect to x: u′=dxd(e2x)=2e2x.
Derivative of v: Differentiate v with respect to x: v′=dxd(3+4x)=4.
Numerator Simplification: Now apply the quotient rule: y′=(3+4x)2(3+4x)(2e2x)−(e2x)(4).
Combine Like Terms: Simplify the numerator: y′=(3+4x)26e2x+8xe2x−4e2x.
Stationary Points: Combine like terms in the numerator: y′=(3+4x)22e2x+8xe2x.
Numerator Factorization: Set the derivative equal to zero to find the stationary points: 0=(3+4x)2(2e2x+8xe2x).
Remaining Factor: The numerator must be zero for the fraction to be zero: 2e2x+8xe2x=0.
Solving for x: Factor out e2x: e2x(2+8x)=0.
Substitute x into Equation: Since e(2x) is never zero, set the remaining factor equal to zero: 2+8x=0.
Calculate Exponent: Solve for x: 8x=−2.
Calculate Denominator: Divide by 8: x = -rac{2}{8}.
Find y-coordinate: Simplify the fraction: x=−41.
Stationary Point Coordinates: Now substitute x=−41 back into the original equation to find the y-coordinate of the stationary point: y=3+4(−41)e2(−41).
Stationary Point Coordinates: Now substitute x=−41 back into the original equation to find the y-coordinate of the stationary point: y=3+4(−41)e2(−41).Calculate the exponent: e2(−41)=e−21.
Stationary Point Coordinates: Now substitute x=−41 back into the original equation to find the y-coordinate of the stationary point: y=3+4(−41)e2(−41).Calculate the exponent: e2(−41)=e−21.Calculate the denominator: 3+4(−41)=3−1=2.
Stationary Point Coordinates: Now substitute x=−41 back into the original equation to find the y-coordinate of the stationary point: y=3+4(−41)e2(−41).Calculate the exponent: e2(−41)=e−21.Calculate the denominator: 3+4(−41)=3−1=2.Now we have the y-coordinate: y=2e−21.
Stationary Point Coordinates: Now substitute x=−41 back into the original equation to find the y-coordinate of the stationary point: y=3+4(−41)e2(−41).Calculate the exponent: e2(−41)=e−21.Calculate the denominator: 3+4(−41)=3−1=2.Now we have the y-coordinate: y=2e−21.The coordinates of the stationary point are (−41,2e−21).
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