<prompt> Mstari huwekwa kulingana naanzapmatrix x y mwishopmatrix anzapmatrix 5 -1 mwishopmatrix t anzapmatrix 2 1 mwishopmatrix. Mstari wa pili umeainishwa naanzapmatrix x y mwishopmatrix anzapmatrix -7 3 mwishopmatrix u anzapmatrix -1 1 mwishopmatrix. Ikiwa theta ni pembe kali inayoundwa na mistari miwili, basi tafuta cos theta.  <response>: Vivekta vya mwelekeo wa mistari ni beginpmatrix 2 1 endpmatrix na beginpmatrix -1 1 endpmatrix. Kosine ya pembe kati ya mwelekeo huu vekta nifracanzapmatrix 2 1 mwishopmatrix cdot anzapmatrix -1 1 mwishopmatrixleft anzapmatrix 2 1 mwishopmatrix kulia kushoto anzapmatrix -1 1 mwishopmatrix kulia frac-1sqrt5 sqrt2 -frac1sqrt 10.Kwa kuwa theta ni kali, cos theta frac1sqrt10. 