Phng trnh , Bt phng trnh v t

Th.s Nguyn Dng T 093.252.8949 LTH & Bi Dng KT ph Thng

Phng trnh , Bt phng trnh v tBi 1: Gii phng trnh

a)

- Phng trnh c chuyn thnh h

- Vy phng trnh cho c 3 nghim.

b)

S:x=1/2; x=1

c)

S: x=2.

d)

S:

e)

- S dng BT Bunhia.

f)

S: x=0

Bi 2: Gii BPT:

a)

S: x1/4

b)

K

- Bin bt phng trnh v dng

- Kt hp K ta c nghim ca BPT l .

c) .

d) .

K:

- Thc hin php nhn lin hp ta thu c BPT

.

- Kt hp K thu c nghim

Cch 2:

- Xt 2 TH:

Vi

Vi

e)

K:

- Vi k

- t . - S: x-3 hoc x1.

Bi 3: Tm m phng trnh sau c nghim:

EMBED Equation.DSMT4 .

Gii: Xt hm s

EMBED Equation.DSMT4 Min xc nh D=.

o hm

y(0)=1>0 nn hm s B Gii hn

BBT

x- +

y +

y

1

-1

Vy phng trnh c nghim khi v ch khi -10 vi mi t. Ta c BBT sau:

t1

g(t) +

g(t)

-3

T BBT suy ra -319VN; m=19: 1 ngh ;m