- Lola agbetunsin

# SAT test tip 2

Sine and Cosine of complementary angles (cofunction) sine( x ) = cos (90-x) sine (2) = 0.034899496 this is the same answer you should get if we try to find cos (90-2) or cos (88)

lets check on the calculator
cos 88 = same . it should be 0.034899496
sin (42) = cos (90-42) = cos (48)
this means that since sin (42) = 0.6691
then cos (48) =0.6691
**Examples:**
sin (2) = 0.0349
cos (88)=0.0349
Sin (50) = 0.7660
Cos (40) = 0.7660
If sin (x) =.8978
then cos (90-x) = 0.8978
If sin (2x) = 0.226789
then cos (90 -2x ) =0.226789
**Try this:**
if sin 3x = 0.5467
then cos _________ = 0.5467
answer:

cos (90 - 3x) = 0.5467