Question

Please help me solve this... many thanks!!

Answer 1

The fundamental equation of trigonometry states that

`\cos^2(x)+\sin^2(x)=1`.

This derives from the fact that any point on the unit circle has coordinates
`(x,y) = (\cos(x),\sin(x))`, together with the fact that the equation of the unit circle is
`x^2+y^2=1`

So, from the fundamental equation you can deduce

`\sin^2(x) = 1-\cos^2(x)`

which in your case leads to

`\sin^2(x) = 1-0.36 = 0.64`