How do you find the exact value of sin^-1[sin(-pi/10)]sin1[sin(π10)]?

1 Answer
Jul 3, 2015

sin^-1[sin(-pi/10)]=-pi/10sin1[sin(π10)]=π10

Explanation:

sin^-1[sin(-pi/10)]sin1[sin(π10)]

A simple way to understand this is from the fact that: color(green)(sin^-1)sin1 (also denoted byt color(green)arcsinarcsin) is the inverse trig function of color(green)sinsin

So if you sinsin an angle, you get an real number that lies between -11 and 11

On the other hand if you sin^-1sin1 the answer got previously, you get back the angle.

In the present case, let's say you originally had the angle -pi/10π10

Now, you when you color(red)sinsin it you obtain sin(-pi/10)sin(π10)

Then, if you color(red)(sin^-1)sin1 it this time you will get back the angle: -pi/10π10

That is sin^-1sin1 of sin(-pi/10)sin(π10) is -pi/10π10