Question

Evaluate: sin2 25o + sin2 65o.

Answer 1

its sin^2 25degree+sin^2 65degree

Answer 2

sin2 25o + sin2 65o =
sin 65o can be written as cos(90 - 25)o
and evaluate it !!!

Answer 3

trig identity :
\[\large \sin (\theta) = \cos (90 - \theta)\]

Answer 4

cos 90=0 and cos 25=?

Answer 5

write \(\large \sin(25)\) as \(\large \cos(90 - 25)\)

Answer 6

which is same as \(\large \cos(65)\)

Answer 7

cos(90-65),cos(25)

Answer 8

but sin^2

Answer 9

see if below makes sense :

\[\large \sin^2 25 +\sin^2 65\]

\[\large \left(\sin 25\right)^2 +\sin^2 65\]

\[\large \left(\cos(90- 25)\right)^2 +\sin^2 65\]

\[\large \left(\cos(65)\right)^2 +\sin^2 65\]

\[\large \cos^2 25 +\sin^2 65\]

\[\large 1 \]

Answer 10

65+65=1 25+65=1?

Answer 11

typo in second line from last :
\[\large \large \cos^2 \color{Red}{65} +\sin^2 65\]

Answer 12

another trig identity :
\[\large \cos^2\theta + \sin^2\theta = 1\]