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Section 6: Functions 81
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Factorials
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The FACT function permits you to handle
permutations and combinations with ease. To calculate the factorial of a
positive integer in the X-register, execute the
FACT function. For example, calculate the number
of ways that six people can line up for a photograph.
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P
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= 6! = 6 × 5 × 4 × 3 × 2 × 1
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The HP-41C places 9.999999999 × 1099 in the X-register and
displays OUT OF RANGE for
factorials of numbers greater than 69.
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Square Roots
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To calculate the square root of a number in the X-register, execute the
function. On the keyboard the function
looks like this: . And when you execute
the function from the display or reassign the function, the name is
SQRT
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Keyboard execution:
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Display execution: SQRT
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Find the square root of 16 using key on the
keyboard:
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Now find the square root of the result using
SQRT in the display:
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