The derivative of y = sin(3x)+cos(4x) is obtained by following the rules of trigonometric properties. The derivative is y' = 3 cos 3x - 4 sin 4x. When we substitute x as pi/6, y' is -2√3. we substitute to y-y1 = m ( x-x1)
y - π/6 = -2√3 (x - π/6)
y = -2√3 x + π/6(1+2√3) = -2√3 x + 2.3374
