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Exam. May 15 th 6:15pm. Be there early Exam rooms: On website http://www.math.ksu.edu/math100/ Exam rooms are by recitation instructor (not me) Bring your k-state student ID. How to study. Focus on your previous exams. Review the problems and your own work Study Guide
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Exam • May 15th 6:15pm. Be there early • Exam rooms: On website • http://www.math.ksu.edu/math100/ • Exam rooms are by recitation instructor (not me) • Bring your k-state student ID
How to study • Focus on your previous exams. • Review the problems and your own work • Study Guide • http://www.math.ksu.edu/math100/spring-2009/FinalExamStudyGuideSpring09.pdf • Take old finals (in realistic conditions) • http://www.math.ksu.edu/course_info/oldtests/100tests/
Your test • 75% questions from your previous tests this semester with the numbers changed • 25% new material • Inequalities • Composition • Exponents & logs • Systems • STUDY YOUR OLD TESTS
Agenda • Today • Functions • Linear problems (equalities, inequalities, systems) • Polynomials (including quadratics) • Thursday • Radicals • Rationals • Exponents and logs
A function is a relationship between two changing variables • An “input” variable • An “output” variable • The result of “doing” the function to the output variable • Both variables change so that the “input” variable always tells you exactly what the “output” variable is. • You never get two outputs for the same input.
Not a Function output input
Intercepts y x-intercept (-2,0) x-intercept (2,0) x y-intercept (0,-4)
Combining Functions • (f+g)(x)=f(x)+g(x) • (f-g)(x)=f(x)-g(x) • (fg)(x)=f(x)*g(x) • (f/g)(x)=f(x)/g(x), g(x)≠0 • (f∘g)(x)=f(g(x))
In picture form f(x) f f(x)g(x) x * g g(x) Is not the same as g f x g(x) f(g(x))
COMPARISON (f∘g)(3)=f(g(3)) (fg)(3)=f(3)g(3) -1≠0
Graphing Transformations • The graph for ƒ(x)+c is the graph of ƒ(x) shifted up by c. • The graph for ƒ(x-a) is the graph of ƒ(x) shifted right by a. • NOTE THE MINUS SIGN • The graph for rƒ(x) is the graph of ƒ(x) stretched vertically by r. • negative r causes the graph to flip vertically. • The graph for ƒ(sx) is the graph of ƒ(x) squished horizontally by s. • Negative s causes the graph to flip horizontally • Note the difference!
Even and Odd • A function ƒ is EVEN if ƒ(-x)=ƒ(x). Example: x2 • A function ƒ is ODD if ƒ(-x)=-ƒ(x). Example: x3 • A function ƒ is NEITHER if ƒ(-x)=something else. Example: x3+1
Cubing to cube root y=x3 x=∛y
Cubing to cube root The relationship between x and y stays the same Only my point of view changes y=x3 x=∛y
How to find a function inverse • ƒ(x)=………….x…………. • Rewrite as y=……………x………… • Solve for x. x=~~~~y~~~~~~ • Rewrite as an inverse ƒ-1(y)=~~~~y~~~~~~ • OPTIONAL: change ys to xs. • ƒ-1(x)=~~~~x~~~~~~ • WARNING: Always check that your inverse is actually a function.
Given f (x) = 7x + 1 on the domain of all real numbers, find f-1(x). Be sure to write your answer as a function of x. • f-1(x) = (1/7)x − 1/7 • f-1(x) = x − 1/7 • f-1(x) = 1/(7x+1) • Both (a) and (c) • None of the above
Given f (x) = 7x + 1 on the domain of all real numbers, find f-1(x). Be sure to write your answer as a function of x. ƒ(x)=7x+1 y=7x+1 (y-1)/7=x x=(1/7)y-(1/7) ƒ-1(y)=(1/7)y-(1/7) ƒ-1(x)=(1/7)x-(1/7) A
Point slope form • The equation of a line with slope m through point (a,b) is • If you don’t know the slope,know two points (a1,b1) and (a2,b2), then the slope m is just the slope formula for those points.
Slope intercept form • Slope intercept form is the “simplest” form of a line • “Simplify” means put in slope intercept form
Doing the same thing to both sides • Adding, Subtracting, Multiplying, Dividing, a number from both sides of the equation. • Changes the value of both sides, but not the equality.
WARNING • Each side is a number. When multiplying (or dividing) multiply (or divide) the whole number.
Solving Inequalitites • When I divide by a negative, I can have the same effect as “moving to the other side” by “flipping the sign” Moved x Answers Match Flipped the sign
Solving a system of equations on your calculator (and showing work) In my calculator, I set the matrix [A] • Solve 4x + 8y - 4z = 8 2x + 3y + 4z = 4 5x + 8y + 1z = 7 Then I used the command rref([A]) The calculator output was So the answer is x=-3.5 y=3 z=0.5
Arithmetic on complex numbers • 1 and i cannot be combined. They are on separate axes. • 1+i can’t be simplified, just like x+y can’t be simplified. • Treat i like a variable and you will be ok. • Remember that i2=-1 and √(-1)=i • This can be simplified
Examples You are not done until you have the real and imaginary parts completely separate
Vertex form • y=a(x-h)2+k • To find an equation of a parabola from vertex (h,k) and point (x1,y1). • Plug in h,k, x1,y1 and solve for a. • Plug in h,k, and a. • Answer should look something like: y=2(x-1)2-2
Standard Form of a Polynomial 3x2+2x-2x4-3 Constant term = y-intercept Leading Term 3x2+2x-2x4-3 Leading Coefficient determines end behavior Degree = number of roots= number of bends +1
Factored Form of a Polynomial 4(x-4)(x--1/3)(x-i)(x--i) Leading Coefficient End Behavior (+ means y is increasing for big x. – means y is decreasing when x is big) Roots
Solving Polynomials • Use the Rational Root Test to come up with guesses for roots. • Use Synthetic Division to test roots and factor the polynomial • When you have only a quadratic left, use the quadratic formula
Rational Root Test 4x3-3x2+2x-5 Factors of -5: {-5,-1,1,5} Factors of 4: {1,2,4} The only possible rational roots of this polynomial are -5/1,-1/1,1/1,5/1,-5/2,-1/2,1/2,5/2,-5/4,-1/4,1/4,5/4
Review: Synthetic Division • x3+x2-4x-4. Root at x=2 1320 2 | 11-4-4 2 6 4 1x3+1x2-4x-4=(x-2)(1x2+3x+2)+0 Add up Multiply to the bottom Add up Multiply to the bottom Add up Multiply to the bottom Add up
You are given the coordinates of the vertex (-8,3) and of a point (-4,7) on a parabola. Find the equation of the parabola. a) y = -.25(x+8)2 - 3 b) y = .25(x+8)2 - 3 c) y = .25(x-8)2 + 3 d) y = .25x2 + 4x + 19 e) Both (c) and (d)
You are given the coordinates of the vertex (-8,3) and of a point (-4,7) on a parabola. Find the equation of the parabola. 7=a(-4- -8)2+3 7=a(4)2+3 4/42=a a=1/4 y=0.25(x+8)2+3 y=0.25(x+8)(x+8)+3 y=0.25x2+4x+19 D
Solving Polynomial Inequalities x2<x3-3x • Get 0 on one side [x2-x3+3x<0] • Graph the polynomial [y=x2-x3+3x] • Convert to an equality [x2-x3+3x=0] • Find the roots x=0, x=0.5+0.5√(13), 0.5-0.5√(13) • Use the roots and the graph to solve the inequality 0.5+0.5√(13)<x<0 OR x>0.5-0.5√(13)
Test each interval Is (3)2+2(3)-(3)3<0 ? Is -12<0 ? YES. <----------------|------------|--------------------|---|----> -1 0 2 3 x<-1 -1<x<0 0<x<2 x>2 NO YES NO YES
Solve the QUADRATIC INEQUALITY:Hint: You might graph the parabola y=(x-3)(x+4) first a) x > - 3 b) x < 4 c) x > 3 or x < - 4 d) - 4 < x < 3 e) None of the above