Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: Rút gọn: A= (Tan∝ + Cot∝) ² – (Tan∝ – Cot∝) ² giúp em bài này với ạ, hứa sẽ vote

Toán Lớp 9: Rút gọn:
A= (Tan∝ + Cot∝) ² – (Tan∝ – Cot∝) ² giúp em bài này với ạ, hứa sẽ vote

Comments ( 2 )

  1. $A=(tan\alpha+cot\alpha)^2-(tan\alpha-cot\alpha)^2=tan^2\alpha+cot^2\alpha+2tan\alpha.cot\alpha-tan^2\alpha-cot^2\alpha+2tan\alpha.cot\alpha=4.tan\alpha.cot\alpha=4$

  2. A=(\tan\alpha+\cot\alpha)^2-(\tan\alpha-\cot\alpha)^2
    A=\tan^2\alpha+2.\tan\alpha.\cot\alpha-\tan^2\alpha+2.\tan\alpha.\cot\alpha-\cot^2\alpha
    A=(\tan^2\alpha-\tan^2\alpha)+(\cot^2\alpha-\cot^2\alpha)+(2\tan\alpha\cot\alpha+2\tan\alpha\cot\alpha)
    A=4\tan\alpha\cot\alpha
    A=4.1
    =4
     

Leave a reply

222-9+11+12:2*14+14 = ? ( )