Question

Using the exact trigonometric ratios of 45 degree,30 degree and 60 degree,evaluate the following,leaving where necessary your answer in surd form. (a) 3 sin 30 degree-2 cos 60 degree (b)(tan 45 degree)(4 cos 60 degree-2 cos 60 degree)

Answer 1

sin 30 = 1/2

thus, we get 3/2 - 2cos 60

cos 60 = 1/2

thus we get 3/2 - 2/2 = 1/2

tan45 = 1

so the equation is just 4cos60 - 2cos60

cos 60 = 1/2, as previously mentioned

thus, we get 2 - 1 = 1.....

btw...I think you can just plug these functions into your calculator to figure these out, it is not too hard.