Given that y = 16x + x^(-1), find the two values of x for which dy/dx = 0
The first thing required is to find out what dy/dx is in terms of x. For this, we need to differentiate y with respect to x which be can so to each term of the polynomial. All you need to do is mutiply the term (e.g. ax^b) by the the exponential, and lower the exponential by 1 (e.g. abx^(b-1). Hence:
dy/dx = 16 - x^(-2)=0
=> need x^(-2)=16
=> 1=16x^2
=> x=1/4 or x=-1/4
JM
Related Maths A Level answers
All answers ▸How do you integrate xcos(x)?
Let y be a function of x such that y=x^3 + (3/2)x^2-6x and y = f(x) . Find the coordinates of the stationary points .
Differentiate x^2 + xy + y^2 =1 implicitly.
(a) Express (1+4*sqrt(7))/(5+2*sqrt(7)) in the form a+b*sqrt(7), where a and b are integers. (b) Then solve the equation x*(9*sqrt(5)-2*sqrt(45))=sqrt(80).