Calc BC
posted by Lynn on .
Let f be the function defined by f(x)=(4x8)/(x^2+5x14)
write an equation of the lien normal to the graph of f at x=1
how?

the line tangent to the graph at (x,y) has slope f'(x)
f'(x) = 4/(x+7)^2
f'(1) = 4/8^2 = 1/16
The line normal to f thus has slope +16
f(1) = 1/2
So, now we have a point (1,1/2) and a slope: 16
So, the line is
y  1/2 = 16(x1)