The curve C with equation y=f(x)y = f(x)y=f(x), x>0x > 0x>0, passes through the point P(9,2)P(9, 2)P(9,2).
Given that f′(x)=2x−5+18x2f'(x) = 2\sqrt{x} - 5 + \frac{18}{x^2}f′(x)=2x−5+x218
find the equation of the normal to C at P. Write your answer in the form ax+by+c=0ax + by + c = 0ax+by+c=0, where aaa, bbb and ccc are integers to be found.
Find f(x)f(x)f(x).
