Question

1. if sin 25° =.4226, find sin 155°. 21. i

Explanation:

Step1: Use the trigonometric identity

We know that \(\sin(180^{\circ}-\alpha)=\sin\alpha\). Here, for \(\sin155^{\circ}\), we can write \(155^{\circ}=180^{\circ} - 25^{\circ}\). So, \(\sin155^{\circ}=\sin(180^{\circ}- 25^{\circ})\).

Step2: Apply the identity

By the identity \(\sin(180^{\circ}-\alpha)=\sin\alpha\), when \(\alpha = 25^{\circ}\), we have \(\sin(180^{\circ}-25^{\circ})=\sin25^{\circ}\).

Answer:

\(0.4226\)