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Question Number 146961 by mathdanisur last updated on 16/Jul/21

(√(sin(x))) ∙ cos(x) < 0

sin(x)cos(x)<0

Answered by TheHoneyCat last updated on 16/Jul/21

this expression _(′′(√)′′)  requires that sin(x)>0  thus cos(x)<0    sin(x)>0⇔x∈∪_(k∈Z) ]2kπ,(2k+1)π[  cos(x)<0⇔x∈∪_(k∈Z) ](2k−^1 /_2 )π,(2k+^1 /_2 )π[

thisexpressionrequiresthatsin(x)>0 thuscos(x)<0 sin(x)>0xkZ]2kπ,(2k+1)π[ cos(x)<0xkZ](2k1/2)π,(2k+1/2)π[

Commented byTheHoneyCat last updated on 16/Jul/21

thus x∈∪_(k∈Z) ]2kπ,(2k+^1 /_2 )π[

thusxkZ]2kπ,(2k+1/2)π[

Commented byTheHoneyCat last updated on 16/Jul/21

or x∈]0,(π/2)[ if you want the canonical angle

orx]0,π2[ifyouwantthecanonicalangle

Commented bymathdanisur last updated on 16/Jul/21

thank you Ser

thankyouSer

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