# SAT test tip 2

August 12, 2019

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

cos (90 - 3x) = 0.5467

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