1+ctg2a=1/sin2a
1+cos2a/sin2a=1/sin2a
(sin2a+cos2a)/sin2a=1/sin2a
1/sin2a=1/sin2a
(т.к. sin2a+cos2a=1)
Объяснение:
1+ctg2a=1/sin2a
1+cos2a/sin2a=1/sin2a
(sin2a+cos2a)/sin2a=1/sin2a
1/sin2a=1/sin2a
(т.к. sin2a+cos2a=1)
Объяснение: