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  • Perplex
    IB Math AASL
    /
    Exponents & Logarithms
    /

    Exponential Algebra

    Edit
    Exponential Algebra

    Exponential Algebra

    Exponents, properties of exponents, and solving exponential equations

    Want a deeper conceptual understanding? Try our interactive lesson!

    Exercises

    No exercises available for this concept.

    Key Skills

    Exponential Notation
    SL Core 1.5

    Exponential expressions are a shortcut for writing the multiplication of a number by itself many times:

    an=a×a×⋯×a​n times​🚫

    Here a is called the base and n the exponent. We say that a is raised to the nth power.


    Note that a1=a, since we have 1×a=a.

    Exponent with zero
    SL Core 1.5

    Any number raised to the power zero is

    a0=1×a×a×⋯×a​0 times​=1🚫

    And since any number multiplied by 0 is 0:

    0n=0,n=0🚫

    When n=0, we have 00, which is technically undefined, but in most contexts is defined to be

    00=1🚫
    Multiplying powers with the same base
    SL Core 1.5

    When multiplying exponentials with the same base, the following rule applies:


    an⋅am    ​=a×a×⋯×a​n times​×a×a×⋯×a​m times​ =a×a×⋯×a​n+m times​ =am+n🚫​
    Exponential of exponential
    SL Core 1.5

    An exponential can be the base of another exponential:

    (am)n=a×⋯×a​m times​×⋯×a×⋯×a​m times​​n times​=anm🚫
    Negative exponents
    SL Core 1.5
    a−n=an1​,a=0🚫
    Dividing exponents with the same base
    SL Core 1.5

    In general,

    aman​=an⋅a−m=an−m,a=0🚫
    Exponents of products & quotients
    SL Core 1.5

    When exponentials with the same power are being multiplied or divided, the bases can be combined:

    anbn=(ab)n🚫
    bnan​=(ba​)n,b=0🚫
    Exponential Equations (Equating Indices)
    SL AA 1.7

    If two exponentials in the same positive base are equal, their exponents must be equal:

    an=am⇔n=m,a>0,a=1🚫


    Exponentials can also appear in equations with one or more unknown:

    (21​)x−1=8x+1
    ⇒(2−1)x−1=(23)x+1
    ⇒21−x=23x+3

    Now we can equate the exponents:

    1−x=3x+3⇒x=−21​