A curve has equation y = 20x −x^2 −2x^3 . The curve has a stationary point at the point M where x = −2. Find the x-coordinate of the other stationary point of the curve.
dy/dx = 20 - 2x - 6x2 = -6x2 - 2x + 20 which factorises to dy/dx = (10 - 6x)(2 + x). This shows that x=-2 and x=10/6=5/3 are stationary points of y = 20x −x2 −2x3.
XY
Related Maths A Level answers
All answers ▸How do I prove (x-2) is a factor of the function f(x) = x^2-4x+4?
Find the coefficient of the x^2 term in in the expansion of (1+x)^4.
How do you find the gradient of a parametric equation at a certain point?
1. (a) Find the sum of all the integers between 1 and 1000 which are divisible by 7. (b) Hence, or otherwise, evaluate the sum of (7r+2) from r=1 to r=142