Question 1152781

{{{cos^2(x)-1.7cos(x)-1.68=0}}}.....factor

{{{cos(x)^2+0.7cos(x) - 2.4cos(x) -1.68 = 0}}}

{{{(cos(x)^2+0.7cos(x)) - (2.4cos(x) +1.68) = 0}}}

{{{cos(x)(cos(x)+0.7) - 2.4(2.4cos(x) -0.7) = 0}}}

{{{(cos(x) - 2.4) (cos(x) + 0.7) = 0}}}


solutions:

{{{cos(x) - 2.4=0}}}=>{{{cos(x)=2.4}}}=>{{{x=cos^-1(2.4)}}}=>{{{x=cos^-1(2.4)}}}-> none

{{{cos(x) + 0.7 = 0}}}=>{{{cos(x)=-0.7}}}=>{{{x=cos^-1(-0.7)}}}

=>{{{x=2.34619}}}  or {{{x=-2.34619 +2pi}}} (result in radians)

=>{{{x=134.4}}}° or {{{x=-134.4+360=225.6}}}°


since solution must be in the interval [{{{0}}},{{{2pi}}}] , =>{{{x=2.34619}}} radians or {{{x=134.4}}}°