Question

Please help me out please!! :)

Answer 1

Starting from the Pythagorean identity, we deduce

`\sin^2(x)+\cos^2(x) = 1 \iff \cos^2(x) = 1-\sin^2(x) \iff \cos(x) = \pm√(1-\sin^2(x))`

If we plug in the value 7/10 for sin(x), we have

`\cos(x) = \pm\sqrt{1-(49)/(100)} = \pm\sqrt{(51)/(100)}=\pm(√(51))/(10)`