</p> <p> sin(-α) = -sinα；cos(-α) = cosα；sin(π/2-α) = cosα；cos(π/2-α) = sinα；
</p> <p> sin(π/2+α) = cosα；cos(π/2+α) = -sinα；sin(π-α) = sinα；cos(π-α) = -cosα；
</p> <p> sin(π+α) = -sinα；cos(π+α) = -cosα；tanA= sinA/cosA；tan（π/2＋α）＝－cotα；
</p> <p> tan（π/2－α）＝cotα；tan（π－α）＝－tanα；tan（π＋α）＝tanα
</p> <p>2、两角和差公式：</p> <p> sin(AB) = sinAcosBcosAsinB</p> <p> cos(AB) = cosAcosBsinAsinB</p> <p> tan(AB) = (tanAtanB)/(1tanAtanB)</p> <p> cot(AB) = (cotAcotB1)/(cotBcotA) </p> <p>3、倍角公式 </p> <p> sin2A=2sinA•cosA</p> <p> cos2A=cosA2-sinA2=1-2sinA2=2cosA2-1</p> <p> tan2A=2tanA/（1-tanA2）=2cotA/(cotA2-1)</p> <p>4、半角公式 </p> <p> tan(A/2)=(1-cosA)/sinA=sinA/(1+cosA);</p> <p> cot(A/2)=sinA/(1-cosA)=(1+cosA)/sinA.</p> <p> sin^2(a/2)=(1-cos(a))/2</p> <p> cos^2(a/2)=(1+cos(a))/2</p> <p> tan(a/2)=(1-cos(a))/sin(a)=sin(a)/(1+cos(a)) </p> <p>5、和差化积 </p> <p> sinθ+sinφ = 2 sin[(θ+φ)/2] cos[(θ-φ)/2]</p> <p> sinθ-sinφ = 2 cos[(θ+φ)/2] sin[(θ-φ)/2]</p> <p> cosθ+cosφ = 2 cos[(θ+φ)/2] cos[(θ-φ)/2]</p> <p> cosθ-cosφ = -2 sin[(θ+φ)/2] sin[(θ-φ)/2]</p> <p> tanA+tanB=sin(A+B)/cosAcosB=tan(A+B)(1-tanAtanB)</p> <p> tanA-tanB=sin(A-B)/cosAcosB=tan(A-B)(1+tanAtanB) </p> <p>6、积化和差 </p> <p> sinαsinβ = -1/2*[cos(α-β)-cos(α+β)]</p> <p> cosαcosβ = 1/2*[cos(α+β)+cos(α-β)]</p> <p> sinαcosβ = 1/2*[sin(α+β)+sin(α-β)]</p> <p> cosαsinβ = 1/2*[sin(α+β)-sin(α-β)]万能公式 </p> <p>7、万能公式</p> <p> </p> <p></p> <p> </p>
sin(a+b)=sinacosb+cosasinb sin(a-b)=sinacosb-cosasinb cos(a+b)=cosacosb-sinasinb cos(a-b)=cosacosb+sinasinb cosacosb=1/2[cos(a+b)+cos(a-b)] sinasinb=1/2[cos(a-b)-cos(a+b)] sinacosb=1/2[sin(a+b)+sin(a-b)] sina+sinb=2sin[1/2(a+b)]cos[1/2(a-b)] sina-sinb=2sin[1/2(a-b)]cos[1/2(a+b)] cosa+cosb=-cos[1/2(a+b)]cos[1/2(a-b)] cosa-cosb=2sin[1/2(a+b)]sin[1/2(a-b)] 后面等会发到你邮箱 我在强制记忆