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cosx + sinxtanx = 2 find all solutions?

find all solutions of the equation in the interval 0,2pi

I understand the subject matter I just need help with understanding how to do this one equation

6 Answers

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  • 1 decade ago
    Favorite Answer

    Change tan x into sinx / cosx. Then we have

    cos x + sin x * (sin x / cos x) = 2

    cos x + sin^2 x / cosx = 2

    Multiply the cosx by (cosx / cosx) and combine the two fractions.

    cos^2 x / cosx + sin^2 x / cosx = 2

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

    Remember: for every real number x we have sin^2 x + cos^2 x = 1.

    (cos^2 x + sin^2 x) / cosx = 2 now becomes

    1 / cos x = 2

    Multply both sides by cos x

    1 = 2cosx

    Divide both sides by 2

    cos x = 1/2

    x = pi/3 or 5pi/3

  • 1 decade ago

    cosx + sinx * tanx = 2

    cosx + sinx * sinx/cosx = 2

    cosx + sin^2x/cosx = 2

    (cosx^2 + sin^2x) / cosx = 2

    1/cosx = 2

    1 = 2cosx

    1/2 = cosx

    arccos 1/2 = arccos cosx

    x = pi/6 or 5pi/3

  • Anonymous
    5 years ago

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    cosx+sinxtanx=2 <=> (cos^2x + sin^2x)/cosx = 2 <=> 1/cosx = 2 <=> cosx = 1/2 = cosTT/3 =>x= TT/3

  • 5 years ago

    Where does the cosine come from in the transition from

    cosx+sin^2x/cosx=2

    to

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

    ?

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  • Anonymous
    5 years ago

    There are endless answers, for, as the graphs of all of these show, sec, cos, sin, tan, cos, csc, etc all go on forever. Just say there are endless answers.

  • cos(x) + sin(x) * tan(x) = 2

    cos(x) + sin(x) * sin(x) / cos(x) = 2

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

    1 / cos(x) = 2

    cos(x) = 1/2

    x = pi/3 , 5pi/3

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