Write the expression $3\sin^2{x} + 4\cos{x}$ in the form $a\cos^2{x} + b\cos{x} + c$. Hence or o

Question

Write the expression $3\sin^2{x} + 4\cos{x}$ in the form $a\cos^2{x} + b\cos{x} + c$. Hence or otherwise, solve the equation $3\sin^2{x} + 4\cos{x} - 4 = 0$, for $0^{\circ} \leq x \leq 90^{\circ}$.

Accepted Answer

(a) $-3\cos^2x+4\cos x+3$ (b) $x=0^\circ,70.5^\circ$ to $1$ d.p.

Trigonometry - Trigonometric Equations

Trigonometry - Trigonometric Equations

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