# value of pi

 0 If we want to calculate area of a circle, We can use the value of pi like this pi = acos(-1.) . How does the inverse function work here and how it gives the value of pi here? Thanks in advance. asked 15 Jul '16, 16:10 shuddha7435 34●1●12

 0 acos() is just a function which calculates cos^-1(x), where x is an angle. We have, cos(180) = -1 (the angle is in degree unit) Now, if we convert the angle from degree to radians, we get, cos(180* (pi/180)) = -1 (we have, 1 degree = pi/180 radians) or, cos(pi) = -1 therefore, pi = cos^-1(-1) which can be expressed in C as: acos(-1) Note that, acos() is just a built in function in C under the header file math.h just like sin(), cos(), tan() or sqrt(), abs() etc. answered 18 Jul '16, 06:55 Najat 539●8
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question asked: 15 Jul '16, 16:10

question was seen: 976 times

last updated: 18 Jul '16, 06:55