Đáp án:
$a)P=\dfrac{a-1}{-\sqrt{a}}\\b)a>1$
Giải thích các bước giải:
`P=(sqrta/2-1/(2sqrta))^2*((sqrta-1)/(sqrta+1)-(sqrta+1)/(sqrta-1))(a>0,a ne 1)`
`a)P=((a)/(2sqrta)-1/(2sqrta))^2*(((sqrta-1)^2-(sqrta+1)^2)/((sqrta-1)(sqrta+1)))`
`P=((a-1)/(2sqrta))^2*((a-2sqrta+1-a-2sqrta-1)/(a-1))`
`P=(a-1)^2/(4a)*(-4sqrta)/(a-1)`
`P=(a-1)/(-sqrta)`
`b)P<0`
`<=>(a-1)/(-sqrta)<0`
Mà `a>0=>sqrta>0`
`=>-sqrta<0`
`=>a-1>0`
`<=>a>1`
Vậy với `a>1` thì `P>0.`
$\text{Đáp án+Giải thích các bước giải:}$
`a) (` $\dfrac{\sqrt{a}}{2}$ - $\dfrac{1}{2\sqrt{a}}$`) .(` $\dfrac{\sqrt{a}-1}{\sqrt{a}+1}$ - $\dfrac{\sqrt{a}+1}{\sqrt{a}-1}$ )= ($\dfrac{a-1}{2\sqrt{a}}$`)².` $\dfrac{(\sqrt{a}-1)²-(\sqrt{a}+1)²}{a-1}$ = $\dfrac{(a-1)²}{4a}$ . $\dfrac{a-2\sqrt{a}+1-a-\sqrt{a}-1}{a-1}$ = $\dfrac{a-1}{4a}$ . `(-4\sqrt{a})`= $\dfrac{1-a}{\sqrt{a}}$b) Để `P<0 ⇔` $\dfrac{1-a}{\sqrt{a}}$ `<0`mà `\sqrt{a} ≥ 0 ⇒ 1-a<0 ⇔ a>1`Vậy để `P<0` thì `a>1`
AI nhanh mk tick 5 sao ạ!!!!!!!! mk cần gấp
Nhớ giải thích!Ai hợp lý nhất được hay nhất nha!
VI. Write the questions with “Did…….?”and give the answer with “Yes/ No: Eg:They played soccer yesterday afternoon - Did they play soccer yesterday afternoon? - Yes, they did./ No, they didn’t. 1. He sent a letter to his penpal last week. ........................................................................................................................................... 2. She taught us English last year. ........................................................................................................................................... 3. They did their homework carefully. ........................................................................................................................................... 4. The Robinsons bought a lot of souvenirs. ........................................................................................................................................... 5. Tourist ate seafood at that famous restaurant. ........................................................................................................................................... 6. The teacher gave her students a lot of homeworks. ........................................................................................................................................... 7. His uncle took him to se Cham temple. ........................................................................................................................................... 8. Liz bought a lot of souvenirs. ........................................................................................................................................... 9. They put the fish in a big bag. ........................................................................................................................................... 10. Ba wore the cap with a dolphin on it. ........................................................................................................................................... VII. Supply the correct verb form, positive or negative. 1/ It stopped raining, so I _____ off my raincoat. (take) 2/ The novel wasn’t very interesting. I _____ it very much. (enjoy). 3/ We went to Kate’s house but she _____ at home. (be) 4/ She was in a hurry, so she _____ time to phone you. (have) 5/ The story was very funny but nobody _____ . (laugh) 6/ Tom was very hungry. He _____ like a horse. (eat) 7/ The room was so cold, therefore we _____ well. (sleep) 8/ It was hard work carrying the bags. They _____ very heavy. (be) 9/ The window was open and a bird _____ into the room. (fly) 10/ It was very hot, so I _____ on the air-conditioner. (turn)
Bạn nào giúp mình câu 4 với 5 đi ạ .
Phân biệt giữa nấm ăn được và không ăn được? Nếu ăn phải nấm độc thì cần phải làm gì, liệt kê ít nhất 5 việc?
Hi vọng có kết quả như ý :)
tại sao $\sqrt{x}$ -2+$\sqrt{x}$+2 = 2$\sqrt{x}$
Cho x y là các số thực thỏa mãn x3−9x^2+30x−20=0và 4y^3+6y^2+6y=7. tính P=x^2+xy−2y^2+10y+2x−7
TÍNH NHANH : 4x ²-12xy+9y ² hộ mik vs nha
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