Question

cos square 45 degree minus sin square 15 degrees

Answer 1

cos 45 = 1/$\sqrt{2}$ sin 45 = 1/$\sqrt{2}$ sin 30 = 1/2
sin 15 = sin45-sin30
    =1/$\sqrt{2}$ -1/2 = 2-tex] \sqrt{2} [/tex]/2tex] \sqrt{2} [/tex]
cos45-sin15 =  2 -tex] \sqrt{2} [/tex]/2tex] \sqrt{2} [/tex]-1/1/$\sqrt{2}$ 
= $\sqrt{2}$ /2/$\sqrt{2}$