Question

помогите пожалуйста решить)

Answer 1

ctg(2(π/4 + x)) = ctg(π/2 + 2x) = - tg2x
sinx = - 15/17   x∈(π; 3π/2)
cosx = - √(1 - (15/17)²) = - √(289 - 225)/289 = - √(64/289) = - 8/17
tgx = sinx/cosx = (- 15/17) : (- 8/17) = 15/8
tg2x = (2tgx)/(1 - tg²x)
tg2x = [2*(15/8)] / [1 - (15/8)²] = (15/4)*(64/(- 161) = - 240/161