Final Flashcards
(57 cards)
A limit only exists when
The lim from the right = lim form the left
A limit DNE when
Function has a different height from the left and right side of x = c, vertical asymptotes, or if f(c) oscilates between 2 fixed values as x approaces c
Process for solving limits
1) Direct Substitution
2) 0/k means lim = 0
3) n/0 means lim DNE
4) 0/0 means do more
Methods for 0/0 limits
Factor, Foil, Rationalize (cojugate), getting rid of complex fractions, etc. Always go back to direct sub to finish the problem
lim as x approaches 0 of sin(x)/x or sin(kx)/kx
1
lim as x approaches 0 of 1 - cosx / x
0
lim as x approaches 0 of tanx/x
1
Definition of continuity (3 rules)
1) f(c) is defined
2) lim x->c f(x) exists
3) lim x->c f(x) = f(c)
Intermediate Value Theorem
If f(x) is continuous on the closed interval [a,b] and k is some height between f(a) and f(b), then there exists some c value between [a,b] such that f(c)=k
Slope of the Secant Line
AROC (y2-y1)/(x2-x1)
Slope of the Tangent Line (Derivative)
IROC
f(x) is not Differentiable When
discontinuous, corner, cusp, or a vertical tangent, different slopes from the left and right
f(x) is Differentiable When
1) Continuous
2) Slope from the right = slope from the left
Power Rule f(x) = x^n
f’(x) = nx^(n-1)
Product Rule d/dx [f(x)g(x)]
f(x)g’(x) + f’(x)g(x)
Quotient Rule d/dx [f(x)/g(x)]
[g(x)f’(x)-f(x)g’(x)]/g(x)g(x)
lo di hi - hi di lo over lo lo
Chain Rule (Most Important)
d/dx [f(g(x))]
f’(g(x)) g’(x)
Work from the outside and work your way in only one derivative at a time
d/dx sinx
cosx
d/dx cosx
-sinx
d/dx tanx
sec(x)^2
d/dx cotx
-csc(x)^2
d/dx secx
sec(x)tan(x)
d/dx csc
-csc(x)cot(x)
Implicit Differentiation
Derive both sides with respect to x. When taking the derivative of a term with y attach a y’ (chain rule). Gather all the y’ on one side and solve for y’