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Thread: help rearranging this

  1. #1
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    help rearranging this

    i am wanting to rearrange to make h the subject h the subject and then b the subject

    S= √(b2-h2)


    can someone please help me

    steve
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  2. #2
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    Is your equation $\displaystyle S = \sqrt{b^2-h^2}$ ?

    If so start by squaring both sides,

    $\displaystyle S = \sqrt{b^2-h^2}$

    $\displaystyle S^2 = b^2-h^2$

    Then adding $\displaystyle h^2$ to both sides

    $\displaystyle S^2+h^2 = b^2$

    Finally taking the square root of both sides.

    $\displaystyle \sqrt{S^2+h^2} = b$

    $\displaystyle b = \sqrt{S^2+h^2} $

    Do you follow?
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  3. #3
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    Quote Originally Posted by sugst893 View Post
    i am wanting to rearrange to make h the subject h the subject and then b the subject

    S= √(b2-h2)


    can someone please help me

    steve
    I assume it's meant to be $\displaystyle \displaystyle S = \sqrt{b^2 - h^2}$ .... (Use h^2 NOT h2 to repesent powers).

    Start by squaring both sides, then make $\displaystyle h^2$ the subject etc.
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  4. #4
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    Quote Originally Posted by pickslides View Post
    Is your equation $\displaystyle S = \sqrt{b^2-h^2}$ ?

    If so start by squaring both sides,

    $\displaystyle S = \sqrt{b^2-h^2}$

    $\displaystyle S^2 = b^2-h^2$

    Then adding $\displaystyle h^2$ to both sides

    $\displaystyle S^2+h^2 = b^2$

    Finally taking the square root of both sides.

    $\displaystyle \sqrt{S^2+h^2} = b$

    $\displaystyle b = \sqrt{S^2+h^2} $

    Do you follow?
    that is great thankyou so much if i want h the subject id do the same but divide doth sides by b is that correct

    thats so great
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  5. #5
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    Quote Originally Posted by sugst893 View Post
    that is great thankyou so much if i want h the subject id do the same but divide doth sides by b is that correct

    thats so great
    No. Post your working so that it can be reviewed.
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  6. #6
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    ok so

    first i would square both sides

    then subtract s^2 from both sides

    giving me h=sqrt{S^2-b^2}

    stephen
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  7. #7
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    No, if you want to make it this way, it's a little different.

    $\displaystyle S = \sqrt{b^2-h^2}$

    Square both sides:

    $\displaystyle S^2 = b^2-h^2$

    Now, Move b^2;

    $\displaystyle S^2 - b^2 = -h^2$

    You see that there is a minus sign? Multiply both sides by -1:

    $\displaystyle -S^2 + b^2 = h^2$

    Rearrange:

    $\displaystyle b^2 - S^2= h^2$

    Now, you take the square root.

    $\displaystyle \sqrt{b^2 - S^2}= h$

    $\displaystyle h = \sqrt{b^2 - S^2}$
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