Answer:
tan(2u)=[4sqrt(21)]/[17]
Step-by-step explanation:
Let u=arcsin(0.4)
tan(2u)=sin(2u)/cos(2u)
tan(2u)=[2sin(u)cos(u)]/[cos^2(u)-sin^2(u)]
If u=arcsin(0.4), then sin(u)=0.4
By the Pythagorean Identity, cos^2(u)+sin^2(u)=1, we have cos^2(u)=1-sin^2(u)=1-(0.4)^2=1-0.16=0.84.
This also implies cos(u)=sqrt(0.84) since cosine is positive.
Plug in values:
tan(2u)=[2(0.4)(sqrt(0.84)]/[0.84-0.16]
tan(2u)=[2(0.4)(sqrt(0.84)]/[0.68]
tan(2u)=[(0.4)(sqrt(0.84)]/[0.34]
tan(2u)=[(40)(sqrt(0.84)]/[34]
tan(2u)=[(20)(sqrt(0.84)]/[17]
Note:
0.84=0.04(21)
So the principal square root of 0.04 is 0.2
Sqrt(0.84)=0.2sqrt(21).
tan(2u)=[(20)(0.2)(sqrt(21)]/[17]
tan(2u)=[(20)(2)sqrt(21)]/[170]
tan(2u)=[(2)(2)sqrt(21)]/[17]
tan(2u)=[4sqrt(21)]/[17]
Answer:
Step-by-step explanation:
The trick is to find the third angle
180 - A - <BCA = <CBA
180 - X - <BCX = <CBX
Everything else is OK
<CBA = <CBX Equals equated to an equal express = an equal expression.
Now by a little slight of hand, you get the two triangles to be equal by ASA, which always works.
Cheating you say? There is no such thing as cheating if it correct and it works.
Answer:
18
Step-by-step explanation:
Sum the parts of the ratio, 3 + 4 = 7
Divide the amount of marbles by 7 to find the value of one part of the ratio
42 ÷ 7 = 6 ← value of 1 part of the ratio, thus
red marbles = 3 × 6 = 18
