lf f(x)=sin6x+cos6x then f′′(x)=
E = cos6x+6cos4x+15cos2x+10(cos5x+5cos3x+10cosx) equals to
What is the value of ∆ if (cos6x + 6cos4x + 15cos2x + 10)/(cos5x + 5cos3x + 10cosx)= ∆cosx ?