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What basic trigonometric identity would you use to verify that sin x cos x tan x =1-cos^(2)x?

Question b of 10which of the following describe an angle with a vertex at a? check all that applyo a. labcов. савd dooo c_baco d. zacb

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.