1)1/49 в степени -x/2=7 2)Упростите tga+tgb/tga-tgb

1) [latex] \frac{1}{49}^{\frac{-x}{2}} = 7 [/latex] [latex](7^{-2})^{\frac{-x}{2}} = 7^{1}[/latex] [latex]7^{\frac{-2*(-x)}{2}} = 7^{1}[/latex] [latex]7^{x} = 7^{1}[/latex] [latex]x = 1[/latex] 2) (tga + tgb)/ (tga - tgb) ; Пусть (tga + tgb) = A  и (tga - tgb) = B A = sina/cosa + sinb/cosb = [sina*cosb + sinb*cosa]/ cosa*cosb = = sin(a+b)/cosa*cosb B = sina/cosa - sinb/cosb = [sina*cosb - sina*cosa]/cosa*cosb* =  =sin(a-b)/cosa*cosb A/B = sin(a+b)/cosa*cosb : sin(a-b)/cosa*cosb = sin(a+b)/sin(a-b)