令x=2cost，则<img src="/Image1/14/14e16ea7fe1508581d7285ca816e34a7.jpg" />等于：（）<br>A:<img src="/Image1/1d/1d305d174422b62d843bdf382e8e66df.jpg" />-16sin<sup>2</sup>t·cos<sup>2</sup>tdt<br>B:-<img src="/Image1/0a/0a4f04ff86c62d862b3a1fee5ee9884c.jpg" />16sin<sup>2</sup>t·cos<sup>2</sup>tdt<br>C:<img src="/Image1/1d/1d305d174422b62d843bdf382e8e66df.jpg" />16sin<sup>2</sup>t·cos<sup>2</sup>tdt<br>D:1<img src="/Image1/0a/0a4f04ff86c62d862b3a1fee5ee9884c.jpg" />6sin<sup>2</sup>t·cos<sup>2</sup>tdt