Express $7 \cos 2x - 2 \sin 2x$ in the form of $R \cos(2x + \alpha)$, where $\alpha$ is i

Question

Express $7 \cos 2x - 2 \sin 2x$ in the form of $R \cos(2x + \alpha)$, where $\alpha$ is in radians. Hence solve $7 \cos 2x - 2 \sin 2x = 5$ for $0 \leq x \leq 2\pi$.

Accepted Answer

sqrt(53) cos(2x + 0.278 rad); x = 0.268, 2.60, 3.41, 5.74 rad

Trigonometry - Trigonometric Equations

Trigonometry - Trigonometric Equations

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