Simplified, $\log_a\sqrt{a}+\log_a(a^2)$ equals:
A$\tfrac32$
B$2$
C$\tfrac72$
D$\tfrac52$
Answer & Solution
Correct answer: D. $\tfrac52$
1. Use $\log_a M+\log_a N=\log_a(MN)$ to combine the two terms.
2. That gives $\log_a\left(\sqrt{a}\cdot a^2\right)$.
3. Write the radical as a power: $\sqrt{a}=a^{1/2}$, so the product is $a^{1/2+2}=a^{5/2}$.
4. Then $\log_a\left(a^{5/2}\right)=\dfrac52$, since $\log_a(a^k)=k$.
5. Answering $2$ drops the contribution of the square-root term entirely.
_Source: NECTA CSEE 2022 Basic Mathematics 041, Question 2: Exponents, Radicals and Logarithms_
Keep practising Exponents, Radicals and Logarithms
Browse all Exponents, Radicals and Logarithms questions for CSEE (Form 4), or explore more Basic Mathematics topics.
Related questions
Spot the intruderComplete the surd workMatch the log law to its formSolve an exponential equationFault the wrong rationalising factorsRationalised, $\dfrac{5+ qrt2}{ qrt6- qrt2}$ simplifies to:The rationalising factor needed to simplify $\dfrac{5+ qrt2}{ qrt6- qrt2}$ is:Solving $8^{x-1}=16$ using the laws of exponents gives $x$ equal to: