Find the requested function value of θ.

If sinθ = 4 over 13, find cos θ

help plz :)

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- Oct 25th 2007, 06:10 PMHelpMePleaseFriendFind the requested function value of θ.
**Find the requested function value of θ.**

If sinθ = 4 over 13, find cos θ

help plz :)

- Oct 25th 2007, 06:22 PMqyzren
draw a triangle! sin θ = 4/13 so opposite is 4 and hypotenuse is 13. just rearrange pythagoras theorem.

- Oct 25th 2007, 06:37 PMHelpMePleaseFriendhmmm
ok i did 13^2 and 4^ 2

i got 169 and 16

do i subtract them from eachother to get 153?

the answer is supposed to be square root of 153 over 13 - Oct 25th 2007, 06:42 PMqyzren
a² + b² = c²

b => +(c²-a²)^0.5

Note: square rooting gives ±, obviously length is not - so we take the + one.