Show that 2sin(x) =(4cos(x)-1)/tan(x) can be written as: 6cos^2(x)-cos(x)-2=0

Rearranging gives:4cos(x)-1 = 2sin(x)tan(x) Substituting in tan(x)=sin(x)/cos(x) gives:4cos(x)-1 = 2sin(x)(sin(x)/cos(x))2sin2(x)=4cos2(x)-4cos(x)Substituting in 2sin2(x) = 2-2cos2(x) (from the trigonometric identity: sin2(x) = 1-cos2(x))2-2cos2(x)=4cos2(x)-4cos(x)Rearranging this by collecting like terms gives:6cos2(x)-cos(x)-2=0

OT

Related Maths A Level answers

All answers ▸

A curve has the equation y = x^4 - 8x^2 + 60x + 7. What is the gradient of the curve when x = 6?


Locate the position and the nature of any turning points in the function: 2x^3 - 9x^2 +12x


A curve has an equation y=3x-2x^2-x^3. Find the x-coordinate(s) of the stationary point(s) of the curve.


Find the roots of y=x^{2}+2x+2