Question

Can someone help me understand what that even function & odd function is, in trignometry

Answer 1

In general,
an <b>even</b> function is one such that
f(x) = f(-x)
For an even function you will see a reflection in the y-axis.

an <b>odd</b> function is one such that
f(x) = -f(-x)
For an odd function you will see a reflection in the origin.

Since sin(x) =-sin(-x) the sine function is odd, and
since cos(x)= cos(-x) the cosine function is even.
lastly since tan(x) = -tan(-x), the tangent function is also odd.

look at the graphs of the trig functions and notice where the reflection takes place.

Since cosecant, secant, and cotangent are simply the reciprocals of the sine, cosine and tangent functions, the properties of these three secondary trig ratios are the same as their corresponding primary ratios.