(E) Separating variables, we get y dy = (1 − 2x) dx. Integrating gives
or
y^2 = 2x − 2x^2 + k
or
2 x^2 + y^2 − 2x = k.
(E)
(E)
(D) Use L’Hôpital’s Rule or rewrite the expression as
(D) For f (x) = tan x, this is .
(E) The parameter k determines the amplitude of the sine curve. For f = k
sin x and g = ex to have a common point of tangency, say at x = q, the
curves must both go through (q, y) and their slopes must be equal at q.