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Math Help - Trig Help

  1. #1
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    Trig Help

    I am having trouble finding the period, and amp from ↓ and simplifying

    1. Whats the period of the graph of y = 2cos^2 5X -1

    period = 2pie/b. I cannot define what the b is. In theory it should be 5, but the power has taken its effect.


    2. For y= 5sinXcosX +1, find its amplitude,period, and its range, and its X intercepts X = all real numbers

    no idea how to start.^^;

    3. simplify sin^2 X + sec^2 X + tan^2 X + cos^2 X
    a.2
    b. 1+sin^2X/cos^2X
    c.2sec^2X
    d.2tan^2X

    here is what i have done, first finding the common denominator.

    = sin^2 X + 1 + Sin^2X + cos^2X
    / cos^2X cos^2X

    = (sin^2X)(Cos^2X)+1+Sin^2X+(cos^2X)(cos^2X)
    / cos^2X

    then i got stuck..
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  2. #2
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    1 problem per thread please.

    \cos^2(x)=\frac{1+\cos(2x)}{2}

    Use that to get the expression in a better form.
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  3. #3
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    Quote Originally Posted by hovermet View Post
    I am having trouble finding the period, and amp from ↓ and simplifying

    1. Whats the period of the graph of y = 2cos^2 5X -1

    period = 2pie/b. I cannot define what the b is. In theory it should be 5, but the power has taken its effect.


    2. For y= 5sinXcosX +1, find its amplitude,period, and its range, and its X intercepts X = all real numbers

    no idea how to start.^^;

    3. simplify sin^2 X + sec^2 X + tan^2 X + cos^2 X
    a.2
    b. 1+sin^2X/cos^2X
    c.2sec^2X
    d.2tan^2X

    here is what i have done, first finding the common denominator.

    = sin^2 X + 1 + Sin^2X + cos^2X
    / cos^2X cos^2X

    = (sin^2X)(Cos^2X)+1+Sin^2X+(cos^2X)(cos^2X)
    / cos^2X

    then i got stuck..
    2. y = 5\sin{x}\cos{x} + 1

    Use the double angle identity for sine:

    \sin{2\theta} = 2\sin{\theta}\cos{\theta}.


    y = 5\sin{x}\cos{x} + 1

     = \frac{5}{2}\cdot 2\sin{x}\cos{x} + 1

     = \frac{5}{2}\sin{2x} + 1


    You should be able to go from here...
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