trig help

alpina · #1 $Old$ January 15th, 2009, 04:01 PM

1. Prove sin(sin^2(x))/(1- cos(x))= 1
2. Solve 2 tan(x)+ (√12) = 0
3. 2cos(^2x) + cos(x)= 1 Write the general solutions.

vincisonfire · #2 $Old$ January 15th, 2009, 04:31 PM

1. If the first identity is really $\frac{sin(sin^2(x))}{1-cos(x)}$ then I think that the statement is false. Take e.g. x=pi/4.
2. $tan(x) = -\frac{\sqrt{12}}{2}$ *use the operator arctan [/math]*tan^{-1} [/math]*
3. This is a quadratic equation. Let $*cos(x) = y$ *then the equation becomes $2y^2+y-1=0$ .*

alpina · #3 $Old$ January 15th, 2009, 04:52 PM

Quote:

Originally Posted by vincisonfire $View Post$

1. If the first identity is really $\frac{sin(sin^2(x))}{1-cos(x)}$ then I think that the statement is false. Take e.g. x=pi/4.
2. $tan(x) = -\frac{\sqrt{12}}{2}$ *use the operator arctan [/math]*tan^{-1} [/math]*
3. This is a quadratic equation. Let $*cos(x) = y$ *then the equation becomes $2y^2+y-1=0$ .*

thanks for your help