Quiz:Piecewise definition of function: Difference between revisions

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<quiz display=simple>
<quiz display=simple>
{Suppose <math>f(x) := \left\lbrace \begin{array}{rl} x^2, & x < 2, x^3, & x \ge 2 \\\end{array}\right.</math> and <math>g(x) := \left \lbrace \begin{array}{rl} x + 1, & x \le 1, 2x + 3, & x > 1 \\\end{array}\right.</math>. What is <math>(f + g)(x)</math>?
{Suppose <math>f(x) := \left\lbrace \begin{array}{rl} x^2, & x < 2\\ x^3, & x \ge 2 \\\end{array}\right.</math> and <math>g(x) := \left \lbrace \begin{array}{rl} x + 1, & x \le 1, 2x + 3, & x > 1 \\\end{array}\right.</math>. What is <math>(f + g)(x)</math>?
|type="()"}
|type="()"}
- <math>\left \lbrace\begin{array}{rl} x^2 + x + 1, & x \le 3 \\ 3x + 3, & x > 3 \\\end{array}\right.</math>
- <math>\left \lbrace\begin{array}{rl} x^2 + x + 1, & x \le 3 \\ 3x + 3, & x > 3 \\\end{array}\right.</math>
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- It is linear but need not be continuous
- It is linear but need not be continuous
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==Composition==
==Composition==



Revision as of 21:48, 19 October 2011

This quiz is related to piecewise definition of function.

Pointwise combination

Syntax error

1 Suppose f(x):={x2,x<2x3,x2 and g(x):={x+1,x1,2x+3,x>1. What is (f+g)(x)?

{x2+x+1,x33x+3,x>3
{x2+x+1,x<33x+3,x3
{x2+x+1,x1x2+2x+3,1<x<2x3+2x+3,x2
{x2+x+1,x<1x2+2x+3,1x2x3+2x+3,x>2
{x2+x+1,x<2x3+2x+3,2x3x2+2x+3,x>3
f+g, the pointwise sum of functions
fg, the pointwise difference of functions
fg, the pointwise product of functions
None of the above, i.e., they are all guaranteed to be piecewise continuous functions on [a,b]
All of the above, i.e., none of them is guaranteed to be a piecewise continuous function on [a,b]

2 Suppose f and g are functions defined on all of R. f is discontinuous at 5 points and g is discontinuous at 3 points. What can we say about f+g?

It is discontinuous at exactly 8 points
It is discontinuous at at least 8 points
It is discontinuous at at most 2 points
It is discontinuous at at least 2 points and at most 8 points
It may be discontinuous at an arbitrarily large number of points.

3 Suppose f and g are functions defined on all of R. f is discontinuous at 5 points and g is discontinuous at 3 points. What can we say about fg?

It is discontinuous at exactly 8 points
It is discontinuous at at least 8 points
It is discontinuous at at most 8 points
It is discontinuous at at least 2 points
It is discontinuous at at most 2 points

4 Suppose f and g are functions defined on all of R. Suppose f is continuous and piecewise linear, with different nonconstant linear piece definitions on the interval (,0],[0,2],[2,). Suppose g is continuous and piecewise linear with different piece definitions on (,1],[1,3],[3,). What can we say about the pointwise product of functions fg?

It is continuous and piecewise linear, with (potentially) different piece definitions on the intervals (,0],[0,1],[1,2],[2,3],[3,)
It is continuous and piecewise quadratic, with (potentially) different piece definitions on the intervals (,0],[0,1],[1,2],[2,3],[3,)
It is continuous and linear with a single piece definition
It is continuous and quadratic with a single piece definition
It is linear but need not be continuous


Composition

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Differentiation

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