If `x` is any non-zero real number, show that `costhetaa n dsintheta` can never equal to `x+1/x ,`

If x is any non-zero real number, show that costheta' a n d ' sintheta can never equal to x+1/x ,

If x is any non-zero real number,show that cos theta and sin theta can never equal to x+(1)/(x)

If x is any real number then show that cos theta cannot be equal to x+ 1/x.

If x is any real number then show that cos theta cannot be equal to x+(1)/(x)

If x be real, show that cos theta cannot be equal to x+(1)/(x) .

If x be real show that costheta cannot be equal to x+1/x.

If c is a non-zero real number and f(x)=|x|/x,show that |f(c)-f(-c)|=2

If f(x)=(|x|)/(x) and c be a non-zero real number, show that |f(c)-f(-c)|=2.

Let x_1,\ x_2,\....,\ x_n values of variable X and let 'a' be non zero real number. Then prove that the variance of the observations a x_1,\ a x_2, ... ,\ a x_n is a^2 Var (X) . Also, find their standard deviation.