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LaddiusMaximus
 5 years ago
find sin 2x, cos 2x, and tan 2x, if cosx= 2/sqrt13 and x terminates in quadrant 2
LaddiusMaximus
 5 years ago
find sin 2x, cos 2x, and tan 2x, if cosx= 2/sqrt13 and x terminates in quadrant 2

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amistre64
 5 years ago
Best ResponseYou've already chosen the best response.0sin(2x) has the formula: sin(2x) = 2sin(x)cos(x) And cos(2x): cos(2x) = cos^2(x)  sin^2(x) = 1  2sin^2(x) = 2cos^2(x) 1 And for tan(2x) we get: tan(2x) = 2tan(x)/(1tan^2(x))

amistre64
 5 years ago
Best ResponseYou've already chosen the best response.0if cos(x) = 2/sqrt(13) we know how to construct a right triangle to find all the other ....stuff....we need. cos = x/r and the pythagorean theorum states: r^2 = x^2 + y^2.

amistre64
 5 years ago
Best ResponseYou've already chosen the best response.0y = sqrt(sqrt(13)^2  (2)^2) y = sqrt(13  4) = sqrt(9) = 3 y = 3; x=2 ; and r = sqrt(13) sin(x) = y/r = 3/sqrt(13) tan(x) = y/x = 3/2

amistre64
 5 years ago
Best ResponseYou've already chosen the best response.0now its all plug and play :) cos(2x) = cos^2  sin^2 cos(2x) = (2/sqrt(13))^2  (3/sqrt(13))^2 cos(2x) = 4/13  9/13 cos(2x) = 5/13

amistre64
 5 years ago
Best ResponseYou've already chosen the best response.0sin(2x) = 2sin(x)cos(x) sin(2x) = 2(3/sqrt(13))(2/sqrt(13)) sin(2x) = 2(6/13) sin(2x) = 12/13

amistre64
 5 years ago
Best ResponseYou've already chosen the best response.0tan(2x) = 2tan(x) / (1tan^2(x)) tan(2x) = 2(3/2) / (1  (3/2)^2) tan(2x) = 3/ (1  9/4) tan(2x) = 3 / (5/4) tan(2x) = 3(4/5) tan(2x) = 12/5 if I didnt mess it up :)

LaddiusMaximus
 5 years ago
Best ResponseYou've already chosen the best response.0that is ridiculous.
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