Work out the point at which the line y = x^2 + 4x + 4 hits the y-axis and the x value of its turning point.

To work out the point at which the line hits the y axis, we need to know where x = 0. In order to do this, we need to set x = 0, and so we are left with x = 4.
To find the turning point, we need to differentiate the equation. We need to find the derivative of y with respects to the derivative to x. To do this, we remove the x power and -1 times the multiple of x, multiplying the value by its original power i.e. x would go to 1 and x^2 would go to 2x. In this case, we would get dy/dx = 2x + 4, and since we know that the turnig point is the point on a graph where the curve's gradient is 0, we set dy/dx = 0. Solving and rearranging for x, we get 2x = 4, and x = -2.

EC

Related Maths GCSE answers

All answers ▸

Using Pythagoras Theorem find the length of the hypotenuse of a right triangle where a=7 cm and b=11 cm. Round to the nearest tenth


The Diagram shows the Triangle PQR. PQ = x cm. PR = 2x cm. Angle QP^R = 30 degrees. The area of the triangle PQR = A cm^2. Show that x = (Squared Root){2A


Solve the simultaneous equations: 4x + y = 25, x - 3y = 16


Prove that the square of an odd number is always 1 more than a multiple of 4