Could anyone help me to solve the following?
Consider the four dirac matrices(what is dirac matrix?) that obey $M_iM_j+M_jM_i=2\delta_{ij}I$, this is usual Kronecker delta. Thus the square of each dirac matrix is unit matrix(how?), and any two distinct dirac matrices anticommute, show that they are traceless.
(what is dirac matrix?)
Google it, or see Encyclopedia of Mathematics.
Thus the square of each dirac matrix is unit matrix(how?),
Put $i=j$.
and any two distinct dirac matrices anti commute,
Put $i\ne j$.
show that they are traceless.
Let $i\ne j$. Consider $\operatorname{tr}\left(M_i(M_j^2)\right)$, which is also equal to $\operatorname{tr}\left((M_iM_j)M_j\right)$.