Therefore, we have proven that d d θ cos ⁡ θ = − sin ⁡ θ {\displaystyle {\frac {\operatorname {d} }{\operatorname {d} \!\theta }}\cos \theta =-\sin \theta } .
بنابراین نشان دادیم که d d θ cos ⁡ θ = − sin ⁡ θ {\displaystyle {\tfrac {\operatorname {d} }{\operatorname {d} \!\theta }}\cos \theta =-\sin \theta } .