Question

Poate cineva sa ma ajute la ex 2, punctul b??

Answer 1

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Answer 2

E = √5 sin 2x -cos 2x, daca tg x =√5/2

√5 sin 2x - cos 2x⇒ √5 sin 2x = cos 2x⇒ (√5 sin 2x)/(cos 2x)=1⇒

E(x) = √5×tg 2x

dar tg 2x = 2tg x /(1-tg²x)

deci E (x) = √5×[2 tg x/(1-tg²x)

[2×(√5/2)] /(1-[(√5)²/4]=√5/[1-(5/4)]=-4√5

E(x) = √5 × (-4√5)=-4×5 =-20