" What "[cos theta,-sin theta],[sin theta,cos theta]]" is orthogonal."

By matrix multiplication from that M=[[cos theta,-sin theta],[sin theta,cos theta]] is orthogonal.

Evaluate |[cos theta, -sin theta], [sin theta, cos theta]|

Show that the matrix [{:( cos theta , sin theta ),(-sin theta , cos theta ):}] is orthogonal

cos theta/(1+sin theta)=(1-sin theta)/cos theta

Simplify, costheta[[cos theta, sin theta],[-sin theta, cos theta]] + sin theta [[sin theta, -cos theta],[cos theta, sin theta]]

cos theta+sin theta=cos2 theta+sin2 theta

If A = [[cos theta, sin theta],[-sin theta, cos theta]] , then what is A^(-1) ?

Verify that [(cos theta, sin theta),(-sin theta, cos theta)] and [(cos theta, - sin theta),(sin theta, cos theta)] are inverse of each other.

Simplify: cos theta[[cos theta , sin theta],[-sin theta , cos theta]]+sin theta[[sin theta, -cos theta],[cos theta ,sin theta]] .

If A= [[cos theta,-sin theta],[sin theta,cos theta]] ,then Adj A is (a) [[cos theta,-sin theta],[cos theta,sin theta]] (b) [[1,0],[0,1]] (c) [[cos theta,sin theta],[-sin theta,cos theta]] (d) [[-1,0],[0,-1]]