The linear approximation at x = 0 to f(x) = \sqrt { 5 + 4 x } is y =

Answer 1

at x=0 the slope is 2/√5
at x=0, y = √5

So, the line there is y = (2/√5)x + √5

http://www.wolframalpha.com/input/?i=plot+y%3D%E2%88%9A%285%2B4x%29%2Cy%3D2%2F%E2%88%9A5+x%2B%E2%88%9A5+for+x+%3D+-2+to+2