How do you find the equation of the line tangent to #f(x) = x^2 + 2x +1#, with the point (-3, 4)?
1 Answer
Jan 27, 2016
y + 4x + 8 = 0
Explanation:
The equation of the tangent is : y - b = m(x - a ) where m
represents the gradient and (a , b ) a point on the line.
Require to find m , (a , b ) is given (-3 , 4 ) Now m = f'(x).
f'(x) = 2x + 2 and f'(-3) = 2(-3) + 2 = - 6 + 2 = - 4 = m
Equation is : y - 4 = -4 ( x + 3 )
ie y - 4 = - 4x - 12
# rArr y + 4x + 8 = 0 #
