Ch.9 Trigonometric ratios Flashcards
what is the cosine rule to find a missing side?
a² = b² + c² - 2bcCosA
what is the cosine rule fo find a missing angle?
CosA = ( b² + c² - a² ) ÷ 2bc
what are the 2 scenarios when you would use the cosine rule?
1 - if you know two sides and the angle in between
2 - if you know all three sides
what is the sine rule when finding a missing angle?
a÷SinA = b÷SinB = c÷SinC
what is the sine rule when finding a missing angle?
SinA÷a = SinB÷b = SinC÷c
how would you find the area of a triangle using trig?
½abSinC
how often does y = sinθ repeat itself?
every 360°
what is the y-intercept of y = sinθ?
0
when does y=sinθ cross the x-axis?
…, -180°, 0°, 180°, 360°, …
how often does y=cosθ repeat itself?
every 360°
what is the y-intercept of y=cosθ?
1
where does y=cosθ Cross the x-axis?
…, -90°, 90°, 270°, 450°, …
how often does y=tanθ repeat itself?
every 180°
what is the y-intercept of y=tanθ?
0
where does y=tanθ have vertical asymptotes?
it has vertical asymptotes at …, -90°, 90°, 270°, …
what does y = tan(x + 45) mean?
the graph of y = tanθ moves to the left by 45 or the x intercepts get 45 subtracted
what does y = sin(x-90) mean?
the graph of y=sinθ moves to the right by 90 or the x intercepts get 90 added to them
what does y = cosx +1 mean?
the graph y = cosx moves up by 1 or has its y - coordinates added to 1
what does y = sinx - 2 mean?
the graph y = sinx gets moved down by 2 or has 2 subtracted from y-coordinates
what does y = 2sinx mean?
the graph of y = sinx gets vertically stretched or the y-coordinates get multiplied by 2
what does y = cos4x mean?
the graph of y = cosx gets horizontally squished or the x-coordinates are multiplied by ¼
what does y = tan( -x ) mean?
the graph of y = tanx is reflected in the y-axis or the x-coordinates are negated
what does y = -sinx mean?
the graph of y = sinx is reflected in the x-axis or the y-coordinates are negated
