Calculus Help Needed

[Guest]

Please help with these problem:
1. Use a half angle identity to remove the square and use the chain rule to find
Integral cos^2(2x)dx

2.if dy/dx=sin(x), and we find the slope field, where will the tangent lines be horizontal on the interval from x=0 to x=2pi.

 

[pka]

\(\displaystyle \L
\begin{array}{l}
1)\;\arccos \left( {\frac{{\sin (1.5) - \sin (1)}}{{1.5 - 1}}} \right) \\
\\
2)\;J' = \frac{{F'G - FG'}}{{G^2 }} \\
\end{array}\)