🕵️ Algebra 2 Functions · Ages 14 to 17 · 0:54
What Is a Function? One Input, One Output
Learn what makes a relation a function with a visual input-output machine. See why one input cannot produce two outputs, then evaluate f(x) = 2x + 1 and spot the rule in an Algebra 2 function example.
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In this video
- 0:00 The double-output mystery
- 0:10 One input gets one output
- 0:22 Try the rule f(x)=2x+1
Transcript
0:01 A comic detective feeds the number two into a mystery machine.
0:05 Out come five and seven. Wait, two answers for one input?
0:11 A function gives every input exactly one output.
0:15 That first machine is not a function. Two has two different answers.
0:22 Now try the rule, f of x equals two x plus one.
0:30 For x equals two, double two and add one. The output is five.
0:41 One input, one output. This rule is a function.
0:47 Different inputs can share an output, but one input cannot split into two.
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