If the equation sin−1(x2+x+1)+cos−1(ax+1)=π2 has exactly two solutions, then a cannot have the integral value/s
-1
1
2
The given equation holds if x2+x+1=ax+1 and −1≤x2+x+1≤1
⇒x(x+1+a)=0 and −1≤x≤0
⇒x=0 or a−1 and −1≤x≤0
∴x=0 is one solution and for another different solution −1≤a−1<0
⇒0≤a<1.
So only integral value a can have is 0