Y'=2x+2⇒2x+2≤0⇒x≤-1
x∈(-∞;-1]
Sin^2t=1-cos^2t
sin^2t= 1-(9/41)^2=1-81/1681
sint=40/41 не подходит
sint=-40/41
tg t=sint/cost
tgt= - 40/41 :41/9 =- 40/9
ctgt= cost/sint
ctgt= 9/41: (-40/41)= 9/41 * 41/40= -9/40
Х:7=35
х= 35*7
х=245
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245:7=35
35=35