Math Is Fun Forum

hi ganesh
choice (a) or(c) are true

3cos^2x+3sinx=3 
3(1-sin^2x)-sinx-2=0
3-3sin^2x-sinx-2=0
3sin^2x+sinx-1=0
if sinx=y
3y^2+y-1=0
this equaition very easy (0 degree to 360 degree)

(x^2+1/x^2)-3(x-1/x)-2+2-2=0  then (x+1/x)^2-3(x-1/x)-4=0    if (x+1/x)=y  y=4 and -1  now we solves (x+1/x)=4 and (x+1/x)=-1     these equaition very easy

y=4
and,y=-1