<p>By semester 2 or 3, you should have a good idea of whether you are doing well in CS and math courses to have a good idea of whether you can, and want to, declare the CS major, applied math major, both, or neither. You can then plan semester 3 and 4 to declare the appropriate major on time.</p>
<p>More information on CS: [Undergraduate</a> L&S CS Students | EECS at UC Berkeley](<a href=“http://www.eecs.berkeley.edu/csugrad/]Undergraduate”>CS Major Information | EECS at UC Berkeley)</p>
<p>More information on math: [Majoring</a> in Mathematics | Department of Mathematics at University of California Berkeley](<a href=“http://math.berkeley.edu/programs/undergraduate/majoring-mathematics]Majoring”>Majoring in Mathematics | Department of Mathematics at University of California Berkeley)</p>