Using the limit definition, how do you differentiate f(x) = 7x + 8f(x)=7x+8?

1 Answer
Nov 2, 2015

See the explanation section below.

Explanation:

f(x) = 7x+8f(x)=7x+8

f'(x) = lim_(hrarr0)(f(x+h)-f(x))/h

= lim_(hrarr0)([7(x+h)+8]-[7x+8])/h

= lim_(hrarr0)(7x+7h+8 - 7x - 8)/h

= lim_(hrarr0)(7h)/h

= lim_(hrarr0)7

= 7

So, f'(x) = 7