For what value of x does 6 sin 2x - 25 o attain... - JAMB Mathematics 1998 Question

y = 6 sin (2x - 25)^o

(\frac{dy}{dx}) = -12 cos(2x - 25^o)

(\frac{dy}{dx}) = 0

-12 cos x (2x - 25^o) = 0

= cos(2x - 25^o) = 0

= 2x - 25^o = cos^-1(0)

= 2x - 25^o

= 90^o

x = (\frac{115}{2})