Cos3A Plus Sinb
1. Problem: Given $A=49.7^\circ$ and $B=67.2^\circ$, we need to find $\cos 3A + \sin B$, rounded to three decimal places.
2. Calculate $3A$:
$$3A = 3 \times 49.7^\circ = 149.1^\circ$$
3. Evaluate $\cos 3A = \cos 149.1^\circ$ and $\sin B = \sin 67.2^\circ$ using a calculator:
$$\cos 149.1^\circ \approx -0.864$$
$$\sin 67.2^\circ \approx 0.922$$
4. Add the two values:
$$\cos 3A + \sin B = -0.864 + 0.922 = 0.058$$
5. The result rounded to three decimal places is:
$$0.058$$