MATLAB: My Matlab gives me a wrong answers what shall I do to fix it

Question

My Matlab gives me a wrong answers what shall I do to fix it? there is an example in the picture I have send I write sin (90) it gives me 0.89 and sin (30) it gives me -0.9880

Answer 1

You did not attach anything, but in any case, sin() requires that its inputs be in radians. If you want sin of degrees use sind()