Saturday

February 28, 2015

February 28, 2015

Posted by **Amy** on Saturday, March 19, 2011 at 10:00am.

(sin x + cos x)^2 + (sin x - cos x)^2 = 2

steps too please

I got 1 for (sin x + cos x)^2

but then what does (sin x - cos x)^2 become since it's minus?

- Math -
**Reiny**, Saturday, March 19, 2011 at 12:07pmsee reply to your earlier post of this question

- Math -
**Anonymous**, Saturday, March 19, 2011 at 5:06pm(a+b)^2=a^2+2*a*b+b^2

(a-b)^2=a^2-2*a*b+b^2

[sin(x)+cos(x)]^2=

[sin(x)]^2 +2*sin(x)*cos(x)+ [cos(x)]^2

[sin(x)-cos(x)]^2=

[sin(x)]^2 -2*sin(x)*cos(x)+ [cos(x)]^2

[sin(x)+cos (x)]^2+[sin(x)-cos (x)]^2=

[sin(x)]^2 +2*sin(x)*cos(x)+ [cos(x)]^2+

[sin(x)]^2 -2*sin(x)*cos(x)+ [cos(x)]^2=

+[cos(x)]^2+[cos(x)]^2+[sin(x)]^2+[cos(x)]^2=

2*[[sin(x)]^2+[cos(x)]^2]=2*1=2

Becouse: [sin(x)]^2+[cos(x)]^2=1

- Math -
**Anonymous**, Saturday, March 19, 2011 at 5:08pm[sin(x)+cos(x)]^2=

[sin(x)]^2 +2*sin(x)*cos(x)+ cos(x)]^2

[sin(x)-cos(x)]^2=

[sin(x)]^2 -2*sin(x)*cos(x)+ cos(x)]^2

**Answer this Question**

**Related Questions**

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

algebra - Can someone please help me do this problem? That would be great! ...

Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...

tigonometry - expres the following as sums and differences of sines or cosines ...

Math - Calculus - The identity below is significant because it relates 3 ...

trig - Reduce the following to the sine or cosine of one angle: (i) sin145*cos75...

Precal - I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A...

Trig - Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < ...

trig - The expression 4 sin x cos x is equivalent to which of the following? (...

math - Can you please check my work. A particle is moving with the given data. ...