tanx= -12/5 x in Q 2.

find
sin2x=
cos2x=
tan2x=

User Icon for Damon Damon answered
12 years ago

triangle is 5, 12, 13

User Icon for Explain Bot Explain Bot answered
11 months ago

To find the values of sin(2x), cos(2x), and tan(2x), we can use the double-angle identities. These identities relate the trigonometric ratios of twice an angle to the trigonometric ratios of the angle itself.

First, we need to find the value of x in the second quadrant (Q2) using the given equation:

tan(x) = -12/5

Since tangent is negative in the second quadrant, we know that tan(x) = -12/5. We can use the inverse tangent function (arctan) to find the angle x:

x = arctan(-12/5)

Next, we can substitute the value of x into the double-angle identities to find sin(2x), cos(2x), and tan(2x):

sin(2x) = 2sin(x)cos(x)
cos(2x) = cos^2(x) - sin^2(x)
tan(2x) = (2tan(x))/(1 - tan^2(x))

Now, let's calculate these values step by step.

Step 1: Finding x in Q2
Using a calculator or math software, calculate the inverse tangent of -12/5:

x ≈ arctan(-12/5) ≈ -67.38 degrees (rounded to two decimal places)

Step 2: Finding sin(2x)
Using the value of x we found in step 1, we can find sin(x) and cos(x):

sin(x) = sin(-67.38°) ≈ -0.9238795325 (rounded to 10 decimal places)
cos(x) = cos(-67.38°) ≈ 0.3826834324 (rounded to 10 decimal places)

Now, substitute these values into the double-angle identity for sin(2x):

sin(2x) = 2sin(x)cos(x) ≈ 2(-0.9238795325)(0.3826834324) ≈ -0.7071067812 (rounded to 10 decimal places)

So, sin(2x) ≈ -0.7071067812 (rounded to 10 decimal places).

Step 3: Finding cos(2x)
Using the values of sin(x) and cos(x) we found in step 2, we can calculate cos(2x) using the double-angle identity:

cos(2x) = cos^2(x) - sin^2(x) ≈ (0.3826834324)^2 - (-0.9238795325)^2 ≈ 0.9238701195 (rounded to 10 decimal places)

So, cos(2x) ≈ 0.9238701195 (rounded to 10 decimal places).

Step 4: Finding tan(2x)
Using the value of tan(x) and the values of sin(x) and cos(x) we found earlier, we can calculate tan(2x) using the double-angle identity:

tan(2x) = (2tan(x))/(1 - tan^2(x)) ≈ (2(-12/5))/(1 - (-12/5)^2) ≈ -0.2298850575 (rounded to 10 decimal places)

So, tan(2x) ≈ -0.2298850575 (rounded to 10 decimal places).

To summarize:
sin(2x) ≈ -0.7071067812 (rounded to 10 decimal places)
cos(2x) ≈ 0.9238701195 (rounded to 10 decimal places)
tan(2x) ≈ -0.2298850575 (rounded to 10 decimal places)