Cosx/4*sinπ/5-sinx/4-cosπ/5=-√2/2
cosasinb-sinacosb=sin(b-a)
sin(π/5-x/4)=-√2/2
sin(x/4-π/5)=√2/2
x/4-π/5=(-1)^n*π/4+πn
x/4=π/5+(-1)^n*π/4+πn
x=4π/5+(-1)^n*π+4πn
X^4-7x^3+6x^2-5x-19 | <u>_x-1</u>
x^4-x^3 x^3+6x^2+12x+7
6x^3+6x^2
6x^3-6x^2
12x^2-5x
12x^2-12x
7x-19
7x-7
+26
(2*3=6+5=11)+(3*3=9+7=16)= 11+16=27