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algebra 2

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I am taking an online class, and cant understand why when I calculate ona ti84 plus an answer I get decimal answer and my teachers answer is sq root, is there something I am not doing on my calculator? How do I convert.

Example, teachers answer to the following was
sin 315deg = -sin 45deg = -sqrt2/2
I got a decimal answer.

  • algebra 2 -

    You should become familiar with two important special triangles
    1. the 45-45-90 right-angled triangle whose sides are in the ratio
    1 : 1 : √2
    2. the 30-60-90 right-angled triangle whose sides are in the ratio of
    1 : √3 : 2


    The question to find sin 315° probably says to find it "exactly"

    I do these in a 3-step process

    1. Where is the angle?
    315 is in IV and in IV the sine is negative

    2. How far from the x-axis ?
    315° is 45° from the x-axis
    The answer to this question will always be an angle between 0 and 90, it will be called the "angle in standard position, or ASP)

    3. Rewrite the question in terms of the ASP

    sin 315 = -sin 45

    From your special triangles
    sin 45 = 1/√2 or √2/2 after rationalizing

    so sin 315 = -sin 45 = -√2/2

  • algebra 2 -

    In the matrix below, which element is a1,2?





    1
    4
    7
    2
    5
    8
    3
    6
    9





    A. 8 C. 6
    B. 5 D. 2
    Examination

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