a function f(x) has a limit as x approaches c if and only if the right hand and the left hand limits at c exist and are equal.
squeeze theorem
If f(x) ≤ g(x) ≤ h(x) for all x ̸= a and limx→a f(x) = limx→a h(x) = L, thenlimx→a g(x) = L
end behavior model
The function g(x) is(a) A right-end behavior model for f if and only if limx→∞f(x)/g(x) = 1(b) A left-end behavior model for f if and only if lim x→−∞f(x)/g(x)
continuity test
removable discontinuity
A function has a removable discontinuity if the function is continuous everywhere except for a "hole" at x = c
infinite discontinuity
A function has an infinite discontinuity at x = c if the function value increases or decreases indefinitely as x approaches c from the left and right.
jump discontinuity
A function has a jump discontinuity at x = c if the function has a left- and right- hand limit, but they do not equal each other.
intermediate value theorem
If f(x) is a continuous function and a < b and there is a value w such that n is between f(a) and f(b), then there is a number c such that a < c < b and f(c) = w
Slope of a Curve at a Point
The slope of a curve y = f(x) at the point P(a, ff(a)) is the number:
The derivative of a function f at the point x=a
The Derivative
The function f whose value is f′(x) = ... provided the limit exists
one sided derivatives and differentiability
A function y = f(x) is differentiable on a closed interval [a,b] if it has a derivative at every interior point of the interval, and if the limits: ... exist at endpoints
f'(a) might fail to exist
A function will not have a derivative at a point P(a, f(a)) where the slopes of the secant lines [f(x)−f(a)] / (x−a) fail to approach a limit as x approaches a. ex. 1. corner 2. cusp 3. vertical tangent 4. discontinuity
implications of differentiability
1. local linearity 2. continuity
derivative of a constant Function
If f is the function with the constant value c, then
power rule for positive integer powers of x
If n is a positive integer, then
the constant multiple rule
If u is a differentiable function of x and c is a constant, the
the sum and difference rule
If u and v are differentiable functions of x, then their sum and difference are differentiable at every point where u and v are differentiable. At such points:
general equation for displacement
derivative of a^x
derivative of e^x
e^x
the product rule
The product of two differentiable functions u and v is differentiable, and
the quotient rule
At a point where v ≠ 0, the quotient y =u/v of two differentiable functions is differentiable, and