math.acos() method is a library method of math module, it is used to get the arc cosine, it accepts a number between -1 to 1 and returns the arc cosine value (in radians) of the given number.
Note: math.acos() method accepts the only number between the range of -1 to 1, if we provide number out of the range, it returns a ValueError - “ValueError: math domain error”, and if we provide anything else except the number, it returns error TypeError - “TypeError: a float is required”.
math.acos(number);
number
– is the number whose arc cosine to be calculated.float
– it returns a float value that is the arc cosine value of the number
# python code to demonstrate example of
# math.acos() method
# importing math module
import math
# number
a = -1
print("acos(",a,") is = ", math.acos(a))
a = 0
print("acos(",a,") is = ", math.acos(a))
a = 0.278
print("acos(",a,") is = ", math.acos(a))
a = 1
print("acos(",a,") is = ", math.acos(a))
Output
acos( -1 ) is = 3.141592653589793
acos( 0 ) is = 1.5707963267948966
acos( 0.278 ) is = 1.2890849198520296
acos( 1 ) is = 0.0
ValueError example
# Importing math library
import math
# Taking input from user
n = int(input("Please enter number to find arc cosine: "))
# Finding cosine
print("Cosine of ", n, " is: ", math.acos(n))
# Initializing number out of range
n = 3
print("Cosine of ", n, " is: ", math.acos(n))
Output
Please enter number to find arc cosine: 1
Cosine of 1 is: 0.0
Traceback (most recent call last):
File "acos1.py", line 12, in <module>
print("Cosine of ",n," is: ",math.acos(n))
ValueError: math domain error
TypeError example
# Importing math library
import math
# Initializing value which is not a number
n = '100'
# Finding cosine
print("Cosine of ", n, " is: ", math.acos(n))
Output
Traceback (most recent call last):
File "acos2.py", line 7, in <module>
print("Cosine of ",n," is: ",math.acos(n))
TypeError: must be real number, not str
In this program, we have declared value of n a string, which is not a number. As said earlier, we got TypeError.
Thanks for reading !
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