Evaluate logarithm of 21: We need to evaluate the logarithm of 21 with base 4. The logarithm of a number is the exponent to which the base must be raised to produce that number.
Express 21 as a power of 4: First, let's express 21 as a power of 4. Since 4 is 22, we can write 21 as 2−1. This is because 21 is the reciprocal of 2, and the reciprocal of a number is equal to that number raised to the power of 40.
Rewrite logarithm using power of 4: Now, we can rewrite the logarithm using the power of 4. Since 2 is the square root of 4, we can express 2 as 41/2. Therefore, 2−1 can be written as (41/2)−1.
Simplify using properties of exponents: Using the properties of exponents, (421)−1 simplifies to 4−21. This is because when you raise a power to a power, you multiply the exponents.
Rewrite logarithm as log base 4: Now we can rewrite the original logarithm as log4(4−21).
Simplify using property of logarithms: Using the property of logarithms that logb(bx)=x, we can simplify log4(4−21) to just −21.
Simplify using property of logarithms: Using the property of logarithms that logb(bx)=x, we can simplify log4(4−21) to just −21.Therefore, the value of log4(21) is −21.
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