If log3 (a2 + a) - log3 (a + 1) = 2 then what is the value of a?
A
3
B
6
C
9
D
27
উত্তরের বিবরণ
Question: If log3 (a2 + a) - log3 (a + 1) = 2 then what is the value of a?
Solution:
log3 (a2 + a) - log3 (a + 1) = 2
⇒ log3 {(a2 + a)/(a + 1)} = 2
⇒ log3 {a(a + 1)/(a + 1)} = 2
⇒ log3 a = 2
⇒ a = 32
⇒ a = 9
0
Updated: 1 day ago
log272 - log218 + log28 = কত?
Created: 6 days ago
A
9
B
3
C
7
D
5
সমাধান:
= log272 - log218 + log28
= log2(72 × 8) - log218
= log2{(72 × 8)/18}
= log232
= log225
= 5log22
= 5 ; [ log22 = 1]
0
Updated: 6 days ago
log3√12 + log3√(3/4) = ?
Created: 1 week ago
A
12
B
18
C
1
D
24
প্রশ্ন: log3√12 + log3√(3/4) = ?
সমাধান:
log3√12 + log3√(3/4)
= log3√{12 × (3/4)} [logaM + logaN = loga(M × N)]
= log3(√9)
= log33
= 1
0
Updated: 1 week ago
loga(b4) = 4c এবং logb(a4)
= 4d হলে, cd = কত?
Created: 1 month ago
A
0
B
1
C
3
D
4
সমাধান:
loga(b4) = 4c
⇒ 4 × loga(b) = 4c [logn(mk) = k logn(m)]
⇒ loga(b) = c
আবার,
logb(a4) = 4d
⇒ 4 × logb(a) = 4d
⇒ logb(a) = d
∴ cd = loga(b) × logb(a)
⇒ cd = 1 ;[logn(m) × logm(n) = 1]
0
Updated: 1 month ago
