Question

If tanx = 0.75, find the value of

i. cos2x + sin2x
2tanx
ii.
for 0° < x < 90°
C0Sx-sinx
-

Answer 1

i. 31/25

ii. 1/5

Explanation:

you know that tanx = 3/4, so you can also find that sinx = 3/5 and cosx = 4/5. Then you can use the double angle identities to find cos2x and sin2x: cos^2(x) - sin^2(x) + 2sinxcosx and substitute the givens to get 31/25. Then, cosx - sinx is obviously 1/5.