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Thread: Trig question help

  1. #1
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    Trig question help

    For this question, how would I find h or the height using trig. I'm assuming you need x but how would I find that?

    Can some please explain it to me simply? I would appreciate it a lot. I'm just getting use to trig so I don't know any complicated things yet..... Thanks!!
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  2. #2
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    Quote Originally Posted by Dgb186 View Post
    For this question, how would I find h or the height using trig. I'm assuming you need x but how would I find that?

    Can some please explain it to me simply? I would appreciate it a lot. I'm just getting use to trig so I don't know any complicated things yet..... Thanks!!
    $\displaystyle \tan(35) = \frac{h}{x}$

    $\displaystyle \tan(20) = \frac{h}{x+500}$

    two equations, two unknowns ... solve the system algebraically.
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  3. #3
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    Quote Originally Posted by Dgb186 View Post
    For this question, how would I find h or the height using trig. I'm assuming you need x but how would I find that?

    Can some please explain it to me simply? I would appreciate it a lot. I'm just getting use to trig so I don't know any complicated things yet..... Thanks!!
    Using skeeter's equations:
    $\displaystyle \tan(35) = \frac{h}{x}$
    $\displaystyle \tan(20) = \frac{h}{x+500}$

    isolate x
    $\displaystyle x = \dfrac{h}{tan(35)}$

    sub in 2nd equation
    $\displaystyle \tan(20) = \dfrac{h}{ \dfrac{h}{tan(35)} +500}$

    1 equation 1 unknown
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    Thank-you for your replies!! To solve the system algebraically do you mean something like this?

    tan(20)* (500+x) = tan 35(x) ?
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  5. #5
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    Quote Originally Posted by Dgb186 View Post
    Thank-you for your replies!! To solve the system algebraically do you mean something like this?

    tan(20)* (500+x) = tan 35(x) ?
    That will produce a value for x.
    What you are seeking is the variable h.
    After you find x, then use it to determine h.

    $\displaystyle \tan(20) \cdot (500+x) =x \tan(35)$

    $\displaystyle 500 \tan(20) + x \tan(20) =x \tan(35)$

    $\displaystyle 500 \tan(20) = x \tan(35) - x \tan(20)$

    $\displaystyle 500 \tan(20) = x \left(\tan(35) - \tan(20)\right)$

    $\displaystyle \dfrac{500 \tan(20)}{\left(\tan(35) - \tan(20)\right)} = x $
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