Results 1 to 3 of 3

Math Help - Max,min of sinx

  1. #1
    Member
    Joined
    Feb 2008
    Posts
    184

    Max,min of sinx

    Hi,

    I know sinx=1 for x= \pi/2\pm\pi*2n

    and sinx=-1 for x= \pi*1.5\pm\pi*2n

    How the above x values change if we have \sqrt sinx

    thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Feb 2010
    Posts
    422
    \sqrt{|\sin x|} will have minima at the zeros of sine and maxima at the extrema of sine, because the square root is monotonic. I'm not sure what to do without those absolute value bars though....
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member mathemagister's Avatar
    Joined
    Feb 2010
    Posts
    191
    Quote Originally Posted by charikaar View Post
    Hi,

    I know sinx=1 for x= \pi/2\pm\pi*2n

    and sinx=-1 for x= \pi*1.5\pm\pi*2n

    How the above x values change if we have \sqrt sinx

    thanks
    Quote Originally Posted by maddas View Post
    \sqrt{|\sin x|} will have minima at the zeros of sine and maxima at the extrema of sine, because the square root is monotonic. I'm not sure what to do without those absolute value bars though....

    Well, you will notice that, as maddas said, you will have "minima at the zeros of sine and maxima at the extrema of sine." The absolute value bars will not be a problem because you don't really have to solve for anything inside them. Think about it logically... the answers will not be the same as for sinx, but twice as frequent (so you must divide the 2n(pi) by 2) because of the absolute value. So, the maxima will be

    \max(\sqrt{|\sin{x}|}) = 1 \quad \text{at} \quad x = \frac{\pi}{2} \pm n \pi

    Maybe you really did mean \sqrt{\sin{x}}, without the absolute value. Then, the maxima will be the same as before, since square rooting a graph will just make it a bit more "squished down," while keeping the overall structure. So, without the absolute value bars, the maxima will remain:

    \max(\sqrt{\sin{x}})=1 \quad \text{at} \quad x=\frac{\pi}{2} \pm 2n\pi

    Hope that helps

    Mathemagister
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. ((1+sinx+icosx)/(1+sinx-icos))^n
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: November 28th 2011, 08:06 PM
  2. Replies: 1
    Last Post: March 25th 2011, 01:27 AM
  3. Prove:(tanx/(1+tanx)) = (sinx/(sinx+cosx))
    Posted in the Trigonometry Forum
    Replies: 7
    Last Post: February 2nd 2011, 09:46 PM
  4. Integral of Ln(Sinx)/Sinx
    Posted in the Calculus Forum
    Replies: 7
    Last Post: January 11th 2010, 03:18 AM
  5. find y' if y=(sinx)^2 + 2^(sinx)
    Posted in the Calculus Forum
    Replies: 3
    Last Post: January 23rd 2009, 06:00 PM

Search Tags


/mathhelpforum @mathhelpforum