Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Verify the given equation:?

sin(x)(1+cot^2 x) = csc(x)

2 Answers

Relevance
  • 4 weeks ago
    Favorite Answer

    The trick is to use identities, and then simplify whatever cancels out, to show that one side becomes the other.

    For example, csc(x) = 1/sin(x), and

    cot(x) = cos(x)/sin(x)

    There are many routes you can use.

    For this example, let's begin inside th bracket.

    change cot^2(x) = cos^2(x) / sin^2(x)

    (1 + cot^2(x)) becomes

    (1 + cos^2(x) / sin^2(x))

    Put all this bracket under the common denominator sin^2(x)

    ( sin^2(x)/sin^2(x) + cos^2(x)/sin^2(x) )

    pull out the common denominator sin^2(x0

    (it divides the whole bracket)

    (sin^2(x) + cos^2(x))/sin^2(x)

    The numerator is a famous identity, where sin^2 + cos^2 = 1

    We have reduced the bracket to

    1/sin^2(x)

    -----

    Let's now rewrite the entire equation using this substitution

    sin(x) (1/sin^2(x)) = csc(x)

    one sine below is cancelled by the sine above, leaving

    1/sin(x) = csc(x)

    which is the definition of a csc = 1/sin

Still have questions? Get your answers by asking now.