<em><span style、"font-family: 'times new roman', times, serif;">cos x+3a<sup>2</sup></span></em>
<em><span style、"font-family: 'times new roman', times, serif;">cos x</span></em>
<em><span style、"font-family: 'times new roman', times, serif;">sin x+6a</span></em>
<em><span style、"font-family: 'times new roman', times, serif;">-sin x</span></em>