please help me please
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2
Answer:
A and C only
Explanation:
Option C is true as
cotα−tanα= sinαcosα − cosαsinα
= sinαcosαcos2α−sin2α
= sinαcosαcos2α
= sin2α2cos2α =2cot2α
tan(45+α)+tan(45−α)
=
1−tan45tanα
tan45+tanα
+
1+tan45tanα
tan45−tanα
=
1−tanα
1+tanα
+
1+tanα
1−tanα
=
1−tan
2
α
(1+tanα)
2
+(1−tanα)
2
=
1−(sec
2
α−1)
1+tan
2
α+2tanα+1+tan
2
α−2tanα
= 2−sec2α2sec2α
=2cos2α−12
=cos2α−sin2α2
= cos2α2 =2secα
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