How do you solve tan(x+pi)+2sin(x+pi)=0tan(x+π)+2sin(x+π)=0?

1 Answer
Jul 31, 2016

For this type of problem, you must use the double angle formulae to expand the parentheses.

Explanation:

The following formulas are extremely important. Be sure to retain them into the future.

![http://study.com/academy/lesson/http://applying-the-sum-difference-identities.html](https://useruploads.socratic.org/20Hg8IkoTR6jDi9TFDpZ_images.jpeg)

Now, using these formulae, we can expand:

(tan(x) + tan(pi))/(1 - tanxtanpi) + 2(sinxcospi + cosxsinpi) = 0tan(x)+tan(π)1tanxtanπ+2(sinxcosπ+cosxsinπ)=0

(tanx + 0)/(1 - tanx xx 0) + 2(sinx(-1) + cosx(0)) = 0tanx+01tanx×0+2(sinx(1)+cosx(0))=0

tanx/1 + 2(-sinx) = 0tanx1+2(sinx)=0

tanx - 2sinx = 0tanx2sinx=0

sinx/cosx - 2sinx =0sinxcosx2sinx=0

(sinx -2sinxcosx)/cosx = 0sinx2sinxcosxcosx=0

sinx - 2sinxcosx = 0 xx cosxsinx2sinxcosx=0×cosx

sinx(1 - 2cosx) = 0sinx(12cosx)=0

sinx = 0 and cosx = 1/2sinx=0andcosx=12

x = 0˚, 180˚, 60˚ and 300˚

Note that these solutions are only in the interval 0˚ <= x <360˚.

Hopefully this helps!