已知sinα+cosαsinα-cosα=3 （1）求tanα；（2）求sinα_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题解答题

已知

sinα+cosα

sinα-cosα

=3 （1）求tanα；（2）求sinαcosα

答案

（1）原式可化为

tanα+1

tanα-1

=3，即tanα+1=3tanα-3，

解得tanα=-2；（6分）

（2）sinαcosα=

sinαcosα

1

=

sinαcosα

sin2α+cos2α

=

tanα

tan2α+1

=

-2

4+1

=-

2

5

（6分）

单项选择题 B型题

肾上腺髓质脂肪瘤的CT特点是（）

A.肿瘤位于肾上腺单侧，小于2cm，低密度网格状，CT值-35~28HU

B.肿瘤位于肾上腺单侧，大于2cm，低密度均匀肿块，CT值35～50HU

C.肿瘤位于肾上腺，单侧多见，直径2～20cm，中央坏死，少数伴钙化，强化显著

D.肿瘤位于肾上腺单侧，体积大，密度不均多伴钙化，侵犯邻近结构

E.肿瘤位于肾上腺单侧，无症状，体积大以脂肪密度为主，CT值-80~-120HU

完形填空

A man was walking along the street when he saw a woman struggling with a large package（包裹）. It was half in and half out of her car.
He was a         kind of man so he went up to the woman and said, "Let me give you a hand with that package. It looks very        ."
"That's very kind of you," the woman said. "I'm having a lot of         with it. I think it's stuck."
"Together we'll soon move it," the man said. "I'll get into the         and take the other end."
"Oh, that's very        . Thank you so much," the woman said gratefully. He got into the back         of the car and took hold of the other end of the package.
"Right," he said, "I'm ready." And he began to push with all his        .
For several minutes the man and the woman struggled with the package. Soon they were both red in face and out of        .
"Let's pause for a minute," the man said. "You're right. It really is        ."
They paused for a few         to wipe the perspiration from their faces and get their breath back.
Then the man said, "Let's try again. Are you        ?"
They         took hold of the package again.
"One, two, three!" the man said, and again they         their struggle with the package.
At last, when they were both        , the man said, "I'm sorry, but the package really seems to be        stuck. I don't think there's any way we can get it out of the car."
"Get it out of the car!" the woman cried. "You fool! I'm trying to get it in!"

B．interesting