Найдите tga если sina = и a (0; п/2)

Tgα=sinα/cosα, cosα=?
sin²α=(5√26/26)²=25*26/26²=25/26
sin²α+cos²α=1
25/26+cos²α=1
cos²α=1/26
cosα=+-√(1/26). α∈(0;π/2), =>cosα>0
cosα=√(1/26)
tgα=(5√26/26) / (1/√26), tgα=5