Results 1 to 2 of 2

Math Help - Subs

  1. #1
    Junior Member
    Joined
    Aug 2007
    Posts
    54

    Subs

    i had a pretest today, and the bonus question involved subs..i dont know how to type them, but its the opposite of powers. the real test will probably have a similar bonus question, and i need to get all the points i can to make up for a test i bombed recently, so can someone please give me a quick lesson on sub qualities?
    also, the question was something like this:
    solve for b
    A=y-(b sub1+ b sub2)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    GAMMA Mathematics
    colby2152's Avatar
    Joined
    Nov 2007
    From
    Alexandria, VA
    Posts
    1,172
    Awards
    1
    Quote Originally Posted by Nightfire View Post
    i had a pretest today, and the bonus question involved subs..i dont know how to type them, but its the opposite of powers. the real test will probably have a similar bonus question, and i need to get all the points i can to make up for a test i bombed recently, so can someone please give me a quick lesson on sub qualities?
    also, the question was something like this:
    solve for b
    A=y-(b sub1+ b sub2)
    I have never heard of that terminology, but I imagine b subN = \frac{1}{b^N}. Therefore, so solve b for your question would go like this...

    A = y - \frac{1}{b} - \frac{1}{b^2}
    A - y = - \frac{1}{b} - \frac{1}{b^2}

    Multiply both sides by -1...
    y - A = \frac{1}{b} + \frac{1}{b^2}

    Multiply both sides by b^2
    b^2(y - A) = b + 1
    b^2(y - A) - b - 1 = 0

    Use quadratic formula to solve for b
    b=\frac{1 \pm \sqrt{1 - 4(-1)(y - A)}}{2(y - A)}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. confused with u-subs problem
    Posted in the Calculus Forum
    Replies: 4
    Last Post: February 22nd 2009, 05:20 AM
  2. Is this u-subs?
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 11th 2009, 09:32 AM
  3. Help with trig subs...
    Posted in the Calculus Forum
    Replies: 3
    Last Post: November 5th 2007, 03:33 PM
  4. subs method / elimination
    Posted in the Algebra Forum
    Replies: 2
    Last Post: April 17th 2007, 02:55 PM
  5. Integration by subs. or parts?
    Posted in the Calculus Forum
    Replies: 5
    Last Post: August 23rd 2006, 05:20 AM

Search Tags


/mathhelpforum @mathhelpforum