Question

Given that sin0=21/29, what is the value of cos0, for 0

Answer 1

The value of sin(0) is given as 21/29. to find cos(0), you can use the fact that

sin^2(0) + cos^2(0) = 1

for any angle 0 in a right-angled triangle.

since sin(0) = 21/29, you can find cos(0) by rearranging the equation.

cos^2(0) = 1 - sin^2(0)

substitute the given value

cos^2(0) = 1 - (21/29)^2

now calculate cos(0)

cos(0) = (+-) sqrt(1-(21/29)^2)

be aware of the positive or negative sign depends on the quadrant in which 0 lies. since sin(0) is positive, 0 is in the first or second quadrant, where cos(0) is also positive.

now calculate the value

cos(0) = sqrt(1-(21/29)^2)

once you perform the calculation, you will get a value of cos(0).

which should be 0.69.

Answer 2

Since sin = opposite / hypotenuse, we can solve for the adjacent. Using Pythagorean thm, adjacent = sqrt(21^2 + 29^2) = 20. Therefore cos(0) = 20/29