# arcsin and arccos

• Oct 23rd 2009, 01:09 PM
alexandrabel90
arcsin and arccos
why is it that arcsin(-y) = -arcsin(y) and that arccos(-y) = π (pi) - arccos(y)?

also, what does the above 2 equations have anything to do with even and odd functions? i have no idea what is even and odd functions by the way..

thank you!!
• Oct 23rd 2009, 01:36 PM
Quote:

Originally Posted by alexandrabel90
why is it that arcsin(-y) = -arcsin(y) and that arccos(-y) = π (pi) - arccos(y)?

also, what does the above 2 equations have anything to do with even and odd functions? i have no idea what is even and odd functions by the way..

thank you!!

An even function is a function such that \$\displaystyle f(-x)=f(x)\$. For example, a parabola \$\displaystyle y=x^2\$ is an even function since: \$\displaystyle f(-x)=(-x)^2=x^2=f(x)\$

An odd function is on in which \$\displaystyle f(-x)=-f(x)\$

Since the sine funciton is odd, the arcsine function is also odd. Therefore, \$\displaystyle Arcsin(-y) = -Arcsin(y)\$
• Oct 23rd 2009, 02:45 PM
alexandrabel90