Toán Chứng minh C bé hơn 0,5 (với 2C = 1-1/3^99) 31/08/2021 By Bella Chứng minh C bé hơn 0,5 (với 2C = 1-1/3^99)
2c=1-(1/3^99) ⇔2c=(3^99-1)/3^99 ⇔c=(3^99-1)/3^99.2 vì(3^99-1)/3^99.2<(3^99)/3^99.2=1/2 =>(3^99-1)/3^99.2<1/2 =>c<1/2 hay c<0,5 Trả lời
Ta có: $2C = 1 – \dfrac{1}{3^{99}}$ $⇒ C = (1 – \dfrac{1}{3^{99}}):2$ $⇒ C = 0,5 – \dfrac{\dfrac{1}{3^{99}}}{2}$ $⇒$ $C < 0,5$ ($đpcm$) Trả lời
2c=1-(1/3^99)
⇔2c=(3^99-1)/3^99
⇔c=(3^99-1)/3^99.2
vì(3^99-1)/3^99.2<(3^99)/3^99.2=1/2
=>(3^99-1)/3^99.2<1/2
=>c<1/2
hay c<0,5
Ta có:
$2C = 1 – \dfrac{1}{3^{99}}$
$⇒ C = (1 – \dfrac{1}{3^{99}}):2$
$⇒ C = 0,5 – \dfrac{\dfrac{1}{3^{99}}}{2}$
$⇒$ $C < 0,5$ ($đpcm$)