Note: You will need to write the degree symbol for the arguments of these trigonometric functions.
As sin(x)=cos(90-x), this means sin10 = cos80 and cos75=15.
So,
LHS = (cos80)(sec80)(sin15)(cosec15)
LHS = (cos 80)(1/cos 80)(sin 15)(1/sin 15)
LHS = 1
Therefore, the identity is true.
