F.2 math 2question????????????

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squareroot(5^2-4^2)=3
sin@=3/5//
tan@=3/4//
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squareroot(3^2-2^2)=squareroot(5)
cosA over tanA +sinA
=squareroot(5)over3/2 over squareroot(5)+2/3
=5/6+2/3
=5/6+4/6
=9/6
=3/2//

1. cos θ=4/5
∴adjacent side= 4
hypotenuse = 5
adj. side^2 + opp. side^2 = hyp.^2 (Pyth. thm)
∴ 4^2 + opp. side^2 = 5^2
16 + opp. side^2 = 25
opp. side^2 = 25 -16
opp. side^2 = 9
opp. side = 3
sin θ = opp. side/hypotenuse
sin θ = 3/5
tanθ = opp. side/adj. side
tanθ = 3/4

2. sinA=2/3
∴opp. side= 2
hypotenuse = 3
adj. side^2 + opp. side^2 = hyp.^2 (Pyth. thm)
adj. side^2 + 2^2 = 3^2
adj. side^2 + 4 = 9
adj. side^2 = 5
adj. side = 2.236067977
cosA = adj. side/hypotenuse
cosA = 2.236067977/ 3
tanA = opp. side/adj.side
tanA = 2/2.236067977
∴ cosA/tanA +sinA
= (2.236067977/ 3)/(2/2.236067977)+2/3

1)
cos@ = 4/5

sin@ = ([5^2 - 4^2]^1/2) / 5

tan@ = 3/4


2)
sinA = 2/3

cosA = (5)^0.5 / 3

tanA = 2 / 5^0.5

draw a triangle la

2007-05-10 18:27:48 補充：
or use calculator