Question
cotA = tan(90degrees- A) True or False
The vectors <4, 5> and <-10, 8> are orthogonal True or False
2<3, 5> = 16 True or False
<2. 3>*<4, 3> =
<2, 6> + <4, 5> =
Find c if a = 3, b = 5, and A = 30degrees=
The vectors <4, 5> and <-10, 8> are orthogonal True or False
2<3, 5> = 16 True or False
<2. 3>*<4, 3> =
<2, 6> + <4, 5> =
Find c if a = 3, b = 5, and A = 30degrees=
Answers
Steve
the co- in the trig functions means co-mplementary angle.
cos(x) = sin(90-x)
cot(x) = tan(90-x)
csc(x) = sec(90-x)
#2 true. review the dot product.
#3 eh? a vector and a scalar?
#4 2*4 + 3*3
if * means dot product
#5 <2+4,6+5>
for the last one, use the law of sines to find B:
sinB/5 = sin30/3
Now, with B, C=180-(A+B) and using the law of cosines,
c^2 = 3^2+5^2-2*3*5cosC
cos(x) = sin(90-x)
cot(x) = tan(90-x)
csc(x) = sec(90-x)
#2 true. review the dot product.
#3 eh? a vector and a scalar?
#4 2*4 + 3*3
if * means dot product
#5 <2+4,6+5>
for the last one, use the law of sines to find B:
sinB/5 = sin30/3
Now, with B, C=180-(A+B) and using the law of cosines,
c^2 = 3^2+5^2-2*3*5cosC