gre考试常用数学公式大全
<p> 1、诱导公式</p><p> <span word="sin">sin</span>=-<span word="sin">sin</span> <span word="cos">cos</span>=<span word="cos">cos</span> <span word="sin">sin</span>=<span word="cos">cos</span> <span word="cos">cos</span>=<span word="sin">sin</span></p><p> <span word="sin">sin</span>=<span word="cos">cos</span> <span word="cos">cos</span>=-<span word="sin">sin</span> <span word="sin">sin</span>=<span word="sin">sin</span> <span word="cos">cos</span>=-<span word="cos">cos</span></p><p> <span word="sin">sin</span>=-<span word="sin">sin</span> <span word="cos">cos</span>=-<span word="cos">cos</span> <span word="tgA">tgA</span>=<span word="tanA">tanA</span>=<span word="sinA">sinA</span>/<span word="cosA">cosA</span></p><p> 2、两角和与差的三角函数</p><p> <span word="sin">sin</span>=<span word="sincos">sincos</span>+<span word="cossin">cossin</span> <span word="cos">cos</span>=<span word="coscos">coscos</span>-<span word="sinsin">sinsin</span> <span word="sin">sin</span>=<span word="sincos">sincos</span>-<span word="cossin">cossin</span> <span word="cos">cos</span>=<span word="coscos">coscos</span>+<span word="sinsin">sinsin</span></p><p> <span word="tan">tan</span>=+<span word="tan">tan</span>)/<span word="tan">tan</span>) <span word="tan">tan</span>=-<span word="tan">tan</span>)/<span word="tan">tan</span>)</p><p> 3、三角函数和差化积公式</p><p> <span word="sin">sin</span>+<span word="sin">sin</span>=2<span word="sin">sin</span>/2)<span word="cos">cos</span>/2) <span word="sinsin">sinsin</span>=2<span word="cos">cos</span>/2)<span word="sin">sin</span>/2)</p><p> <span word="cos">cos</span>+<span word="cos">cos</span>=2<span word="cos">cos</span>/2)<span word="cos">cos</span>/2) <span word="cos">cos</span>-<span word="cos">cos</span>=-2<span word="sin">sin</span>/2)<span word="sin">sin</span>/2)</p><p> 4、积化和差公式</p><p> <span word="sinsin">sinsin</span>=-1/2 <span word="coscos">coscos</span>=1/2</p><p> <span word="sincos">sincos</span>=1/2</p><p> 5、二倍角公式</p><p> <span word="sin">sin</span>=2<span word="sincos">sincos</span> <span word="cos">cos</span>=<span word="cos">cos</span>^2-<span word="sin">sin</span>^2=2<span word="cos">cos</span>^2-1=1-2<span word="sin">sin</span>^2</p><p> 6、一元二次方程的解-<span word="b">b</span>+/2<span word="a">a</span> -<span word="b">b</span>-<span word="b">b</span>+/2<span word="a">a</span></p><p> 根与系数的关系 <span word="X">X</span>1+<span word="X">X</span>2=-<span word="b">b</span>/<span word="a">a</span> <span word="X">X</span>1<span word="X">X</span>2=<span word="c">c</span>/<span word="a">a</span>注：韦达定理</p><p> 判别式 <span word="b">b</span>2-4<span word="a">a</span>=0 注：方程有相等的两实根</p><p> <span word="b">b</span>2-4<span word="ac">ac</span>0 注：方程有一个实根</p><p> <span word="b">b</span>2-4<span word="ac">ac</span>0 注：方程有共轭复数根</p><p> 7某些数列前<span word="n">n</span>项1+2+3+4+5+6+7+8+9++<span word="n">n</span>=<span word="n">n</span>/2 1+3+5+7+9+11+13+15++=<span word="n">n</span>2</p><p> 2+4+6+8+10+12+14++=<span word="n">n</span> 12+22+32+42+52+62+72+82++<span word="n">n</span>2=<span word="n">n</span>/6</p><p> 13+23+33+43+53+63+<span word="n">n</span>3=<span word="n">n</span>22/4 12+23+34+45+56+67++<span word="n">n</span>=<span word="n">n</span>/3</p><p> 8、正弦定理 <span word="a">a</span>/<span word="sinA">sinA</span>=<span word="b">b</span>/<span word="sinB">sinB</span>=<span word="c">c</span>/<span word="sinC">sinC</span>=2<span word="R">R</span>注： 其中<span word="R">R</span> 表示三角形的外接圆半径</p>
页:
[1]