Differentiate the equation y = (2x+5)^2 using the chain rule to determine the x coordinate of a stationary point on the curve.
Use the chain rule as this is a composite function. Let u=2x+5.So the original equation becomes y=(u)^2.Using the chain rule: dy/dx = dy/du * du/dxdy/du = 2udu/dx = 2So dy/dx= 4uSince u=2x+5, dy/dx = 4(2x+5)dy/dx = 8x+20Since stationary points occur when dy/dx=0, let 8x+20=0So 8x=-20So x=-2.5.
DP
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