Q. Find the coordinates of the point on the curve y=x+12(x−5) where the gradient is 45.
Find Derivative: First, we need to find the derivative of y with respect to x to determine the gradient of the curve. The function is y=x+12(x−5). Using the quotient rule, the derivative y′ is given by: y′=x+1[x+1⋅2]−[2(x−5)⋅(21)(x+1)−21] = x+12x+1−x+1x−5
Set Equal to 45: Next, set the derivative equal to 45 to find the x-coordinate where the gradient is 45. x+12x+1−x+1x−5=45 Cross-multiplying to clear the fraction: 4(2x+1−x+1x−5)=5(x+1) 8x+1−x+14(x−5)=5x+5
Simplify and Solve: Simplify and solve for x:8x+1−x+14(x−5)=5x+5Let's multiply through by x+1 to clear the square root:8(x+1)−4(x−5)=5x+5x+18x+8−4x+20=5x+5x+14x+28=5x+5x+1
More problems from Find derivatives using logarithmic differentiation