Question

cos314degrees 40' =
a. -.7030
b. .7112
c. .7030
d. -.7112

Answer 1

1st, its in the 4th quadrant so cos is +ve right?

Answer 2

@mathsux4real now convert the 40' to degrees:
60' =1degree
40' = ??

Answer 3

We have
\[\cos (314\ degrees, 40')\]
we know
\[\cos (270+x)=\sin x\]
so it's
\[\sin (44\ degrees, 40')\]
we know that
\[\sin 45=\frac{1}{\sqrt 2}=0.707\]
so
\[\sin (44\ degrees, 40')<0.707\ ( \text{since 44 degrees, 40'<45 degrees})\]
I think you can find the answer now

Answer 4

Quadrant IV so cos is +, 40' in degrees is .666, now cos of 314.66(degrees) is .703

Answer 5

@mathsux4real
40' = 40/60degree = 2/3
remember its in 4th quad so ref angle = 360- 314 2 /3 = 45 1/3 = 45.333
cos 45.3333= 0.7030

Answer 6

@mathsux4real we don't need calculator for this, did you follow my explanation?

Answer 7

Thank you guys!

Answer 8

Wish I could give more than one medal