Prove that (1-cos2x)/sin(2x) = tan(x) where x ≠ nπ/2

Starting from the left hand side we can substitute the sin and cos sum and difference formulas. These are sin(A+B) = sinAcosB + cosAsinBand cos(A+B) = cosAcosB - sinAsinBBecause x = A = B when substituted these formulae become:sin(2x) = sin(x)cos(x) + sin(x)cos(x) = 2sin(x)cos(x)cos(2x) = cos2(x) - sin2(x) When substituted into the question(1-cos2(x) + sin2(x))/2sin(x)cos(x) = 2sin2(x)/2sin(x)cos(x) = sin(x)/cos(x) = tan(x)This is as required

JB

Related Maths A Level answers

All answers ▸

Find the stationary points of the curve f(x) =x^3 - 6x^2 + 9x + 1


How to differentiate with respect to x, xsin2x.


What is a geometric series?


Separate (9x^2 + 8x + 10)/(x^2 + 1)(x + 2) into partial fractions.