Question

In: Advanced Math

prove by epsilon-delta definition that f:R->R given by f(x)=x^3 is continuous at x=2

prove by epsilon-delta definition that f:R->R given by f(x)=x^3 is continuous at x=2

Solutions

Expert Solution

Proof : f : R R is continuous at x0 if for all > 0 there exists > 0 for all x R:

Therefore f(x) = x3 and x0 = 2

Therefore for all > 0 there exists > 0 for all x R > 0

( | x - 2 | < | x3 - 23 | = | (x-2)(x2 + 2x + 4)| < where is bigger

| (x-2)(x2 + 2x + 4)| =

Therefore f(x) = x3 is continuous at x = 2


Related Solutions

Using the epsilon-delta definition prove Lim of x^2 =4 when x approaches 2
Using the epsilon-delta definition prove Lim of x^2 =4 when x approaches 2
Let f : R → R be a function. (a) Prove that f is continuous on...
Let f : R → R be a function. (a) Prove that f is continuous on R if and only if, for every open set U ⊆ R, the preimage f −1 (U) = {x ∈ R : f(x) ∈ U} is open. (b) Use part (a) to prove that if f is continuous on R, its zero set Z(f) = {x ∈ R : f(x) = 0} is closed.
a) use the sequential definition of continuity to prove that f(x)=|x| is continuous. b) theorem 17.3...
a) use the sequential definition of continuity to prove that f(x)=|x| is continuous. b) theorem 17.3 states that if f is continuous at x0, then |f| is continuous at x0. is the converse true? if so, prove it. if not find a counterexample. hint: use counterexample
Prove that {f(x) ∈ F(R, R) : f(0) = 0} is a subspace of F(R, R)....
Prove that {f(x) ∈ F(R, R) : f(0) = 0} is a subspace of F(R, R). Explain why {f(x) : f(0) = 1} is not.
1. Use the ε-δ definition of continuity to prove that (a) f(x) = x 2 is...
1. Use the ε-δ definition of continuity to prove that (a) f(x) = x 2 is continuous at every x0. (b) f(x) = 1/x is continuous at every x0 not equal to 0. 3. Let f(x) = ( x, x ∈ Q 0, x /∈ Q (a) Prove that f is discontinuous at every x0 not equal to 0. (b) Is f continuous at x0 = 0 ? Give an answer and then prove it. 4. Let f and g...
Show epsilon arguments for any limit proofs: 1)Prove: If limf(x)x->a=L and c∈R, then limx->acf(x)=cL. 2) Prove:...
Show epsilon arguments for any limit proofs: 1)Prove: If limf(x)x->a=L and c∈R, then limx->acf(x)=cL. 2) Prove: If lim f(x)x->a = L and lim g(x)x->a = M, then lim(f(x)+g(x))​​​​​​​x->a = L+M. 3) Find a counterexample to the converse of #2. 4) Prove: If lim f(x)​​​​​​​x->a = L and lim g(x)​​​​​​​x->a = M, then lim(f(x)g(x)) ​​​​​​​x->a= LM. 5) Find a counterexample to the converse of #4.
9. Let f be continuous on [a, b]. Prove that F(x) := sup f([x, b]) is...
9. Let f be continuous on [a, b]. Prove that F(x) := sup f([x, b]) is continuous on [a, b]
. Let f(x) = 3x^2 + 5x. Using the limit definition of derivative prove that f...
. Let f(x) = 3x^2 + 5x. Using the limit definition of derivative prove that f '(x) = 6x + 5 Then, Find the tangent line of f(x) at x = 3 Finally, Find the average rate of change between x = −1 and x = 2
This question shows 3 possible models. Delta R^2 is the adjusted R^2 value. Then F is...
This question shows 3 possible models. Delta R^2 is the adjusted R^2 value. Then F is the test statistic for adjusted R^2. The significance columns show the p-values for each measurement. The best model is the one with the lowest p-value for F. The table below summarizes nested multiple regression models used to predict a person’s quality of life score. Model 1 Model 2 Model 3 est. sig. est. sig. est. sig. intercept 16.68 <.001 9.16 <.001   7.57 <.001 size...
a) State the definition that a function f(x) is continuous at x = a. b) Let...
a) State the definition that a function f(x) is continuous at x = a. b) Let f(x) = ax^2 + b if 0 < x ≤ 2 18/x+1 if x > 2 If f(1) = 3, determine the values of a and b for which f(x) is continuous for all x > 0.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT