<span>Sin(x-п/4)+cos(x-п/4)=sin2x
sinxcos</span>π/4-cosxsinπ/4+cosxcosπ/4+sinxsinπ/4=sin2x
√2/2*sinx-√2/2*cosx+√2/2*cosx+√2/2*sinx=sin2x
√2*sinx-2sinxcosx=0
√2sinx(1-√2cosx)=0
sinx=0⇒x=πk,k∈x
cosx=1/√2⇒x=+-π/4+2πk,k∈z
5-2b-7-10b-3c-5x-(18ca-63cy-12xa+42xy)-(55ap+45ac-77yp-63yc)-12-11p-9c= -14-12b-12c-5x-11p-18ca+63cy+12xa-42xy-55ap-45ac+77yp+63yc=
2log2(3)+log7(2)-log7(14)=2log2(3)+log7(2/14)=2log2(3)+log7(1/7)=2log2(3)-1=log2(9)-1
log7(1/7)=log7(7^-1)=-1*log7(7)=-1
<span>Если понравилось решение - нажимай "спасибо" и "лучший" (рядом с кнопкой "спасибо") :)</span>
A^2-9b^2=(a)^2-(3b)^2=(a-3b)(a+3b); x^2y^2-1=(xy)^2-1^2=(xy-1)(xy+1); 49x^2-121a^2=(7x)^2-(11a)^2=(7x-11a)(7x+11a); c^2d^2-m^2=(cd)^2-(m)^2=(cd-m)(cd+m).