Question

Verify each of the following by evaluating the logarithms.

log10(103) + log10(104) = log10(107)

Answer 1

log₁₀(10³) + log₁₀(10⁴)

= log₁₀( 10³ × 10⁴ )

= log₁₀( 10³⁺⁴)

= log₁₀( 10⁷)

Explanation:

Given:

log₁₀(10³) + log₁₀(10⁴) = log₁₀(10⁷)

Now,

we know the property of log function that

log(A) + log(B) = log(AB)

therefore,

applying the above property on the LHS, we get

log₁₀(10³) + log₁₀(10⁴) = log₁₀( 10³ × 10⁴ )

also,

xᵃ + xᵇ = xᵃ⁺ᵇ

therefore,

log₁₀( 10³ × 10⁴ ) = log₁₀( 10³⁺⁴)

= log₁₀( 10⁷)

Hence,

LHS = RHS

Hence proved