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80 lines
2.5 KiB
Plaintext
80 lines
2.5 KiB
Plaintext
The '''SQR''' function returns the square root of a numerical value.
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{{PageSyntax}}
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:: square_root = '''SQR('''value''')'''
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* The ''square root'' returned is normally a [[SINGLE]] or [[DOUBLE]] numerical value.
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* The ''value'' parameter can be any '''positive''' numerical type. '''Negative parameter values will not work!'''
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* Other exponential root functions can use fractional exponents([[^]]) enclosed in '''parenthesis only'''. EX: {{text|root <nowiki> = </nowiki> c ^ (a / b)|green}}
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''Example 1:'' Finding the hypotenuse of a right triangle:
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{{CodeStart}} '' ''
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A% = 3: B% = 4
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PRINT "hypotenuse! ="; SQR((A% ^ 2) + (B% ^ 2)) '' ''
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{{CodeEnd}}
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{{OutputStart}}
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hypotenuse = 5
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{{OutputEnd}}
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''Example 2:'' Finding the Cube root of a number.
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{{CodeStart}} '' ''
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number = 8
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cuberoot = number {{Cl|^}} (1/3)
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PRINT cuberoot '' ''
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{{CodeEnd}}
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{{OutputStart}}
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2
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{{OutputEnd}}
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''Example 3:'' Negative roots return fractional values of one.
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{{CodeStart}} '' ''
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number = 8
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negroot = number {{Cl|^}} -2
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PRINT negroot '' ''
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{{CodeEnd}}
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{{OutputStart}}
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.015625
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{{OutputEnd}}
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:''Explanation:'' A negative root means that the exponent value is actually inverted to a fraction of 1. So x ^ -2 actually means the result will be: 1 / (x ^ 2).
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''Example 4:'' Fast Prime number checker limits the numbers checked to the square root (half way).
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{{CodeStart}}
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DEFLNG P
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DO
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PRIME = -1 'set PRIME as True
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INPUT "Enter any number to check up to 2 million (Enter quits): ", guess$
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PR = {{Cl|VAL}}(guess$)
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IF PR {{Cl|MOD}} 2 THEN 'check for even number
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FOR P = 3 TO {{Cl|SQR}}(PR) STEP 2 'largest number that could be a multiple is the SQR
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IF PR {{Cl|MOD}} P = 0 THEN PRIME = 0: EXIT FOR 'MOD = 0 when evenly divisible by another
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NEXT
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ELSE : PRIME = 0 'number to be checked is even so it cannot be a prime
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END IF
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IF PR = 2 THEN PRIME = -1 '2 is the ONLY even prime
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IF PR = 1 THEN PRIME = 0 'MOD returns true but 1 is not a prime by definition
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IF PRIME THEN PRINT "PRIME! How'd you find me? " ELSE PRINT "Not a prime, you lose!"
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LOOP UNTIL PR = 0 '' ''
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{{CodeEnd}}
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{{OutputStart}}
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Enter any number to check up to 2 million (Enter quits): 12379
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PRIME! How'd you find me?
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{{OutputEnd}}
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<center>''Note:'' Prime numbers cannot be evenly divided by any other number except one.</center>
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''See also:''
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*[[MOD]] {{text|(integer remainder division)}}
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*[[^]] {{text|(exponential operator)}}
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*[[Mathematical Operations]]
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*[[Mathematical_Operations#Derived_Mathematical_Functions|Derived Trigonometric Functions]]
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{{PageNavigation}}
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