Mấy bn giúp mik câu này với ạ   :<

Thu gọn
S = \(\dfrac{1}{4}+\dfrac{1}{4^2}+\dfrac{1}{4^3}+\dfrac{1}{4^4}+\dfrac{1}{4^5}+\dfrac{1}{4^6}+...+\dfrac{1}{4^{29}}+\dfrac{1}{4^{30}}\)

GT | AB // CD
      | AC // BD
––––––––––––
KL | AB = CD
     | AC = BD

Sử dụng “Although”; “though”; “in spite of”; “despite”

Công thức: Although/Though + s + v, s + v; 

In spite of/ Despite + noun/ ving, s + v)

He is rich but he isn’t happy. (Although)

Cars cause pollution but people still want them. (Although) 

Mr. Nam was successful in his life although he came from a poor family. (despite)

Though he is intelligent, he can’t do all these tests well. (in spite of) 

In spite of his much experience in machinery, he didn’t succeed in repairing this machine. (Although)

Don’t shout at her in spite of her laziness. (though) 

It was raining heavily but I went swimming. (in spite of)

Though Lan is beautiful and intelligent, she is never proud of herself. (In spite of )

Lan is admired (được ngưỡng mộ) by her friends because she is intelligent. (Because of)

We don’t spend much time on our housework because  a lot of devices for the home were invented. ( because of) 

We always trust (tin tưởng) Nam because he is wise and honest.( because of)

a, Nếu tia At không cắt yy'

=> At // yy'

=> At trung với Ax (vì xx' // yy')

Mà At là phân giác góc xAb

=> At nằm giữa Ax và AB

=> At không trùng Ax

=> At cắt yy'

b, 

Bạn xem lại đề. C ở đâu vậy?

a, Nếu tia At không cắt yy'

=> At // yy'

=> At trung với Ax (vì xx' // yy')

Mà At là phân giác góc xAb

=> At nằm giữa Ax và AB

=> At không trùng Ax

=> At cắt yy'

b, 

Bạn xem lại đề. C ở đâu vậy?