Question

If sin(x) = 0.28, what is cos(90° - x)

Answer 1

$\bf \textit{Cofunction Identities} \\\\ sin\left(\frac{\pi}{2}-\theta\right)=cos(\theta) \qquad cos\left(\frac{\pi}{2}-\theta\right)=sin(\theta) \\\\\\ tan\left(\frac{\pi}{2}-\theta\right)=cot(\theta)\qquad cot\left(\frac{\pi}{2}-\theta\right)=tan(\theta) \\\\\\ sec\left(\frac{\pi}{2}-\theta\right)=csc(\theta)\qquad csc\left(\frac{\pi}{2}-\theta\right)=sec(\theta)$

therefore, sin(x) = cos(90° - x).