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 find the minimum of the equation sin^2(x) + 4sin(x)?
Find the inverse of a 2x2 matrix
Find the first 3 terms, in ascending powers of x, of the binomial expansion of (2 – 9x)^4 giving each term in its simplest form.
Given that y=(4x+1)^3sin 2x , find dy/dx .